Consider the following statements: Statement I. Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions. Statement II. Silica-bearing clay is mixed with limestone while manufacturing cement. Statement III. Limestone is converted into lime during clinker production for cement manufacturing. Which one of the following is correct in respect of the above statements?

(a) Both Statement II and Statement III are correct and both of them explain Statement I

(c) Only one of the Statements II and III is correct and that explains Statement I

(d) Neither Statement II nor Statement III is correct

Consider the following statements: Statement-I. Of the two major ethanol producers in the world, i.e., Brazil and the United States of America, the former produces more ethanol than the latter. Statement-II. Unlike in the United States of America where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil. Which one of the following is correct in respect of the above statements?

(b) Both Statement I and Statement II are correct but Statement II does not explain Statement I

(c) Statement I is correct but Statement II is not correct

Consider the following statements: Statement-I. In India, State Governments have no power for making rules for grant of concessions in respect of extraction of minor minerals even though such minerals are located in their territories. Statement-II. In India, the Central Government has the power to notify minor minerals under the relevant law. Which one of the following is correct in respect of the above statements?

(b) Both Statement I and Statement II are correct but Statement II does not explain Statement I

(c) Statement I is correct but Statement II is not correct

Consider the following statements: Statement-I. Sumed pipeline is a strategic route for Persian Gulf oil and natural gas shipments to Europe. Statement-II. Sumed pipeline connects the Red Sea with the Mediterranean Sea. Which one of the following is correct in respect of the above statements?

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

Consider the following statements: Statement-I. Recently, Venezuela has achieved a rapid recovery from its economic crisis and succeeded in preventing its people from fleeing/emigrating to other countries. Statement-II. Venezuela has the world's largest oil reserves. Which one of the following is correct in respect of the above statements?

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

Consider the following statements: Statement-I. India, despite having uranium deposits, depends on coal for most of its electricity production. Statement-II. Uranium, enriched to the extent of at least 60%, is required for the production of electricity. Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I

(b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I

Consider the following statements: Statement-I. According to the United Nations' 'World Water Development Report, 2022', India extracts more than a quarter of the world's groundwater withdrawal each year. Statement-II. India needs to extract more than a quarter of the world's groundwater each year to satisfy the drinking water and sanitation needs of almost 18% of world's population living in its territory. Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I

(b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I

Geography

Prelims · Geography · 46 questions

Minerals, energy & industry

Every UPSC Prelims question on this topic, 2016–2026, newest first. Tap an option to check yourself; the answer and explanation open below it.

Asked in 9 of 11 years · most in 2025 (6)

UPSC syllabus: “Indian and World Geography-Physical, Social, Economic Geography of India and the World.” See the full syllabus →

Showing 1–30 of 46, newest first.

Prelims 2026 · Q95

Medium Provisional key

Which of the following statements about Rare Earth Elements (REEs) and Critical Minerals is/are correct?

1.Modern technological innovations including Artificial Intelligence, robotics and space exploration extensively utilise Rare Earth Elements (REEs).
2.China has the highest share in mining of REEs followed by India.
3.The Government of India launched the National Critical Mineral Mission (NCMM) in 2025 to establish a robust framework for self-reliance in the critical mineral sector.
4.Rare Earth Elements are a set of 13 metallic elements.

Select the answer using the code given below:

Answer & explanation

Answer: (a) 1 and 3 only

Statements 1 and 3 are correct: REEs feed high-technology products such as magnets for EVs and wind turbines, and the National Critical Mineral Mission was launched in 2025. Statement 2 is wrong because China leads mining by a huge margin but India is far behind several other countries, and statement 4 is wrong because there are 17 rare earth elements, not 13.

✓ 1. Rare earth magnets are central to electric mobility, renewable energy, electronics and defence applications, and REEs such as dysprosium and neodymium go into wind-turbine magnets.
✗ 2. USGS shows China far ahead in 2025 mine production (270,000 tonnes REO), but India (2,900 tonnes) is well behind the United States (51,000), Australia, Burma and Thailand, so India is not second.
✓ 3. PIB records that the Government of India launched the NCMM in 2025 to build a robust framework for self-reliance in critical minerals (Cabinet approval was on 29 January 2025).
✗ 4. A Ministry of Mines/DAE reply in the Lok Sabha notes that REE has 17 elements, not 13.

Remember · There are 17 rare earth elements (15 lanthanides plus scandium and yttrium). NCMM was launched in 2025. China dominates mining; India is a minor producer.

Sources

PIB: India’s Rare Earth Strategy: Manufacturing, Corridors, and Global Integration ↗ “With the consumption of Rare Earth Permanent Magnets expected to double by 2030 due to rapid growth in electric mobility, renewable energy, electronics, and defence applications”
USGS: Mineral Commodity Summaries 2026, Rare Earths (world mine production) ↗ “China 270,000 270,000 44,000,000 Greenland — — 1,500,000 India 2,900 2,900”
PIB: National Critical Mineral Mission (9 Apr 2025) ↗ “The Government of India launched the National Critical Mineral Mission (NCMM) in 2025 to establish a robust framework for self-reliance in the critical mineral sector.”
PIB: Lok Sabha reply on import of rare earth metals (2 Apr 2025) ↗ “Note:REE has 17 elements. HS codes 280530 and 2846 pertain to REE as a whole and not to a particular element.”

Question and answer: UPSC's provisional GS Paper I (2026, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q6

Medium

Consider the following statements:

I.India has joined the Minerals Security Partnership as a member.
II.India is a resource-rich country in all the 30 critical minerals that it has identified.
III.The Parliament in 2023 has amended the Mines and Minerals (Development and Regulation) Act, 1957 empowering the Central Government to exclusively auction mining lease and composite license for certain critical minerals.

Which of the statements given above are correct?

Answer & explanation

Answer: (c) I and III only

India became the 14th member of the US-led Mineral Security Partnership in June 2023, and the MMDR Amendment Act, 2023 let the Centre alone auction mining leases and composite licences for listed critical minerals. But India is far from self-sufficient: it depends mostly on imports for minerals such as lithium, cobalt and nickel.

✓ I The Ministry of Mines told Parliament that India joined the Mineral Security Partnership as its 14th member in June 2023.
✗ II India identified 30 critical minerals in June 2023 precisely because supply is a risk; for several of them, including lithium, cobalt and nickel, it relies mostly on imports.
✓ III The 2023 amendment empowered the Central Government to exclusively auction mining leases and composite licences for critical minerals in Part D of the First Schedule; the States still grant the lease and keep the revenue.

Remember · Critical minerals: 30 identified (June 2023); MSP member since June 2023; MMDR Amendment 2023 lets the Centre auction them while States keep the revenue.

Sources

PIB (Ministry of Mines), Strengthening of Mineral Supply Chains, 7 August 2023 ↗ “India has become 14th member of the Mineral Security Partnership (MSP) in June 2023.”
PIB (Ministry of Mines), Union Minister Pralhad Joshi unveils List of Critical Minerals for India ↗ “Disclosing that 30 critical minerals have been identified in the report released today, the Minister stated”
PIB (Ministry of Mines), Measures Initiated to Attain Self-reliance in Critical Minerals ↗ “Critical and deep-seated minerals such as Cobalt, Lithium, Nickel, Gold, Silver, and Copper are difficult to explore and mine as compared to surfacial or bulk minerals. The country is mostly dependent on imports of these minerals.”
PIB (Ministry of Mines), Parliament Passes Mines and Minerals (Development & Regulation) Amendment Bill, 2023 ↗ “Another major amendment passed by the Parliament is to empower the Central Government to exclusively auction mining lease and composite licence for certain critical minerals”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q31

Medium

Consider the following statements:

Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions.
Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement.
Statement III: Limestone is converted into lime during clinker production for cement manufacturing.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (b) Both Statement II and Statement III are correct but only one of them explains Statement I

Cement is among the largest single industrial sources of carbon dioxide, about 7% of global emissions according to the International Energy Agency. Both manufacturing facts are true, but only Statement III explains the emissions: heating limestone (calcium carbonate) to make lime releases carbon dioxide directly, on top of the fuel burnt in the kiln. Mixing silica-bearing clay with limestone is simply part of the recipe.

✓ Statement I The International Energy Agency puts the cement sector's share of global carbon dioxide emissions at about 7%, which is well above 5%.
✓ Statement II Cement needs limestone plus silica and alumina, which come mainly from clay or shale; this is true but does not by itself produce the carbon dioxide.
✓ Statement III In the kiln, calcium carbonate breaks down into calcium oxide (lime) and carbon dioxide; this 'process emission' is the main reason cement is so carbon-intensive, so III explains I.

Remember · Cement CO2 is about 7% of global emissions (IEA); most comes from calcination (CaCO3 → CaO + CO2) in clinker making, the rest from kiln fuel.

📘 Read it in NCERT: Class 10 Science, Ch 1 (practise this chapter) · Class 10 Contemporary India – II, Ch 6 (practise this chapter)

Sources

International Energy Agency: Cement technology roadmap plots path to cutting CO2 emissions 24% by 2050 (copy of the IEA news page) ↗ “The cement sector is the third-largest industrial energy consumer in the world, responsible for 7% of industrial energy use, and the second industrial emitter of carbon dioxide, with about 7% of global emissions.”
NCERT Class 10 · Science, Chapter 1 “Decomposition of calcium carbonate to calcium oxide and carbon dioxide on heating is an important decomposition reaction used in various industries. Calcium oxide is called lime or quick lime. It has many uses – one is in the manufacture of cement.”
NCERT Class 10 · Contemporary India – II, Chapter 6 “This industry requires bulky and heavy raw materials like limestone, silica and gypsum.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q38

Medium

Consider the following statements:

I.Carbon dioxide (CO2) emissions in India are less than 0.5 t CO2/capita.
II.In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region.
III.Electricity and heat producers are the largest sources of CO2 emissions in India.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (c) II and III only

India emits about 2 tonnes of CO2 per person, four times the 0.5 t in Statement I. It is the world's third-largest emitter, behind China and the United States, so within Asia-Pacific it is second after China. Power and heat generation is the biggest emitting activity, so II and III are correct.

✗ I The IEA puts India's per capita emissions at around 2 tonnes, less than half the world average of 4.6 tonnes, but far above 0.5 t.
✓ II India is the third-largest source of global energy-related CO2 (after China and the US). China is the only bigger emitter in Asia-Pacific, which makes India second in the region.
✓ III India's own report to the UNFCCC shows energy industries (mainly electricity and heat generation) as the largest contributor within the energy sector, with a 56.53% share of the sector's 2020 emissions.

Remember · India's CO2: about 2 t per person (world about 4.6 t); third-largest emitter globally, second in Asia-Pacific after China; power and heat generation is the largest source.

Sources

IEA: CO2 Emissions in 2023 (per capita) ↗ · reference work “However, India’s per capita emissions remain very low, at around 2 tonnes, less than half the world average of 4.6 tonnes. … India surpassed the European Union to become the third largest source of global emissions in 2023.”
Government of India: India's Fourth Biennial Update Report to the UNFCCC (BUR-4), GHG inventory 2020 ↗ “Within the energy sector, energy industries are the largest contributor with a 56.53 per cent (12,65,328 GgCO2e) of total emissions”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q43

Easy

In the context of electric vehicle batteries, consider the following elements:

I.Cobalt
II.Graphite
III.Lithium
IV.Nickel

How many of the above usually make up battery cathodes?

Answer & explanation

Answer: (c) Only three

In a lithium-ion cell the cathode is a metal-oxide material built from lithium with nickel, cobalt (and manganese), as in the common NMC type. Graphite is the anode material, not part of the cathode. So three of the four elements make up cathodes.

✓ I Cobalt is one of the metals in the active cathode material.
✗ II Graphite forms the anode of the cell, not the cathode.
✓ III Lithium is a cathode mineral (the IEA lists lithium, nickel, cobalt and manganese for the cathode).
✓ IV Nickel is a main cathode metal; nickel-rich cathodes are a key trend in EV batteries.

Remember · EV battery cathode: lithium with nickel, cobalt (and manganese). Anode: graphite.

Sources

IEA: The Role of Critical Minerals in Clean Energy Transitions (2021), battery minerals ↗ · reference work “Cells typically account for 70% to 85% of the total battery weight, and contain a number of minerals in the active cathode material (e.g. lithium, nickel, cobalt and manganese), anode (e.g. graphite), and current collector (e.g. copper)”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q45

Medium

Consider the following substances:

I.Ethanol
II.Nitroglycerine
III.Urea

Coal gasification technology can be used in the production of how many of them?

Answer & explanation

Answer: (b) Only two

Coal gasification turns coal into syngas, which is then converted into fuels and chemicals. India's Ministry of Coal lists ethanol among these products and describes the Talcher plant converting syngas to ammonia and then urea. Nitroglycerine is made by nitrating glycerine with nitric and sulphuric acids and is not one of the coal-gasification products, so only two of the three qualify.

✓ I The Ministry of Coal includes ethanol among the liquid fuels made from syngas and notes that a policy change is under way to include ethanol from the coal gasification route.
✗ II Nitroglycerine (glyceryl trinitrate) comes from nitrating glycerine with mixed nitric and sulphuric acids; it is not a syngas product.
✓ III At Talcher, coal blended with pet-coke is gasified to syngas, converted into ammonia and then into urea.

Remember · Coal gasification gives syngas, then methanol, ethanol, ammonia and urea (Talcher fertiliser plant). Nitroglycerine comes from glycerine and nitrating acids, not from syngas.

Sources

Ministry of Coal: National Coal Gasification Mission (100 MT Coal Gasification by 2030), syngas products ↗ “Liquid Fuels such as Methanol, Ethanol, Synthetic diesel and Chemical and Petrochemicals like Methanol derivatives, Olefins, Propylene, Mono-Ethylene Glycol (MEG), nitrogenous fertilizers including Ammonia … Coal blended with pet-coke up to 25% shall be gassified to produce syngas, which shall be converted into Ammonia and subsequently to 1.27 Mt tonnes of neem coated Urea annually.”
PubChem (US National Library of Medicine, NIH), Nitroglycerin: Methods of Manufacturing (from HSDB) ↗ “It is prepared by continuous two-phase nitration of glycerol in anhydrous mixed acid. The mass ratio of pure anhydrous glycerol (H2O less than 0.5%) and 50:50 mixed acid is 1:5.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q60

Medium

Consider the following activities:

I.Production of crude oil
II.Refining, storage and distribution of petroleum
III.Marketing and sale of petroleum products
IV.Production of natural gas

How many of the above activities are regulated by the Petroleum and Natural Gas Regulatory Board in our country?

Answer & explanation

Answer: (b) Only two

Only II and III are regulated. The Petroleum and Natural Gas Regulatory Board Act, 2006 covers refining, processing, storage, transportation, distribution, marketing and sale of petroleum, petroleum products and natural gas, and it expressly leaves out the production of crude oil and natural gas.

✗ I Producing crude oil is upstream work and is excluded from the Board's remit.
✓ II Refining, storage and distribution are named activities under the Act.
✓ III Marketing and sale of petroleum products are named activities under the Act.
✗ IV The Act excludes the production of natural gas, although transporting, distributing and selling it are regulated.

Remember · PNGRB (Act of 2006) regulates refining, storage, transport, distribution, marketing and sale of petroleum and natural gas, but not upstream production of crude oil or natural gas.

Sources

The Petroleum and Natural Gas Regulatory Board Act, 2006 (No. 19 of 2006), Section 1(4), on the PNGRB website ↗ “It applies to refining, processing, storage, transportation, distribution, marketing and sale of petroleum, petroleum products and natural gas excluding production of crude oil and natural gas.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q63

Medium

Consider the following statements:

Statement-I: Of the two major ethanol producers in the world, i.e., Brazil and the United States of America, the former produces more ethanol than the latter.
Statement-II: Unlike in the United States of America where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (d) Statement I is not correct but Statement II is correct

Statement I is wrong because the United States, not Brazil, is the world's largest ethanol producer. Statement II is correct: corn is the main feedstock in the United States and sugarcane in Brazil.

✗ Statement-I The United States produced over 16 billion gallons of ethanol in 2024; the same data table puts Brazil at roughly 9 billion gallons, so Brazil is second.
✓ Statement-II Most US ethanol is made from corn, while Brazil mainly uses sugarcane.

Remember · The US is the top ethanol producer (mostly from corn); Brazil is second (mainly from sugarcane). Together they make about 80 per cent of the world's ethanol.

Sources

US Department of Energy, Alternative Fuels Data Center: Global Ethanol Production by Country or Region ↗ “The United States is the world's largest producer of ethanol, having produced over 16 billion gallons in 2024. … The vast majority of U.S. ethanol is produced from corn, while Brazil primarily uses sugarcane.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q70

Medium

Consider the following statements about 'PM Surya Ghar Muft Bijli Yojana':

I.It targets installation of one crore solar rooftop panels in the residential sector.
II.The Ministry of New and Renewable Energy aims to impart training on installation, operation, maintenance and repairs of solar rooftop systems at grassroot levels.
III.It aims to create more than three lakhs skilled manpower through fresh skilling, and up-skilling, under scheme component of capacity building.

Which of the statements given above are correct?

Answer & explanation

Answer: (d) I, II and III

All three statements match the Ministry's own guidelines for the scheme. The programme aims at one crore residential rooftop solar installations, MNRE plans grass-root training in installing, operating, maintaining and repairing rooftop systems, and the capacity-building component targets more than 3 lakh skilled workers.

✓ I The first key objective of the programme is to achieve 1 crore rooftop solar system installations in the residential sector.
✓ II The Capacity Building guidelines say MNRE intends to train technicians, electricians, installers and others in installation, operation, maintenance and repair of rooftop solar systems at grass-root level.
✓ III The capacity-building component aims to create more than 3 lakh skilled workers through fresh skilling and up-skilling, of whom at least 1 lakh are to be solar PV technicians.

Remember · PM Surya Ghar (approved 29 Feb 2024): one crore rooftop solar installations in homes; capacity building targets 3 lakh+ skilled workers, at least 1 lakh solar PV technicians.

Sources

Ministry of New and Renewable Energy: Guidelines for PM-Surya Ghar: Muft Bijli Yojana, Central Financial Assistance component ↗ “The key objectives of the programme are: a) To achieve 1 crore rooftop solar system (RTS) installation in residential sector.”
Ministry of New and Renewable Energy: Guidelines for PM-Surya Ghar: Muft Bijli Yojana, Capacity Building ↗ “The Ministry of New and Renewable Energy (MNRE) intends to impart training on installation, operation, maintenance and repairing of solar roof top systems at grass root level. … To create more than 3 lakh skilled manpower, through fresh skilling, and up-skilling, under scheme component of capacity building, out of which at least 1,00,000 will be Solar PV Technicians.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q79

Easy

Consider the following pairs:

	Country	Resource-rich in
I.	Botswana	Diamond
II.	Chile	Lithium
III.	Indonesia	Nickel

In how many of the above rows is the given information correctly matched?

Answer & explanation

Answer: (c) All the three

All three rows are correct: Botswana's economy is built on diamonds, Chile holds the largest lithium reserves in Latin America and is a leading lithium producer, and Indonesia has the world's largest nickel reserves.

✓ I Botswana is a diamond economy; the World Bank says its diamond wealth has driven decades of economic and social progress, and diamonds are still dominant in its economy.
✓ II Chile is first in order of size among the three Latin American countries (Chile, Argentina, Brazil) that hold large lithium reserves, and the World Bank puts it second among lithium miners, after Australia.
✓ III Indonesia holds the world's largest nickel reserve and is the world's largest nickel producer; it banned nickel ore exports in 2014 to build domestic processing.

Remember · Botswana: diamonds. Chile: lithium. Indonesia: nickel, the world's largest reserve, used in steel and EV batteries.

Sources

Botswana country page, World Bank Group ↗ “Botswana’s diamond wealth has supported decades of economic and social progress, but the country’s traditional growth model is under increasing pressure.”
Latin America and the Caribbean in a Greening World: Critical Minerals, World Bank (2024) ↗ “Of the 8 countries with the largest lithium reserves, 3 are in LAC (Chile, Argentina, and Brazil in order of magnitude) and account for 47% of the world total.”
Nickel, Steel and Cars: Export Ban and Domestic Value-Added in Indonesia, World Bank Policy Research Working Paper 11249 (2025) ↗ “Indonesia has the world’s largest reserve of nickel, which is a crucial input to produce iron and steel, and a primary ingredient for batteries that are essential for the production of electric vehicles (EVs).”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2025 · Q89

Medium

Consider the following statements:

Statement-I: In India, State Governments have no power for making rules for grant of concessions in respect of extraction of minor minerals even though such minerals are located in their territories.
Statement-II: In India, the Central Government has the power to notify minor minerals under the relevant law.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (d) Statement I is not correct but Statement II is correct

Statement I is wrong. Mines and minerals are a State subject, subject to Union control, and under the Mines and Minerals (Development and Regulation) Act, 1957 the State Governments frame the rules for concessions in minor minerals. Statement II is right: under the same Act the Central Government can notify further minerals as minor minerals.

✗ Statement-I Section 15(1) of the Mines and Minerals (Development and Regulation) Act, 1957 empowers the State Government to make rules regulating the grant of quarry leases, mining leases and other concessions for minor minerals. The Constitution's State List also covers regulation of mines and mineral development, subject to Union control.
✓ Statement-II Section 3(e) of the Act defines minor minerals as building stones, gravel, ordinary clay and ordinary sand (other than sand used for prescribed purposes) and any other mineral the Central Government declares, by notification in the Official Gazette, to be a minor mineral.

Remember · Minor minerals: State Governments make the concession rules; the Central Government notifies what counts as a minor mineral (MMDR Act, 1957).

Sources

The Mines and Minerals (Development and Regulation) Act, 1957 (India Code, Legislative Department), section 15(1) ↗ “15. Power of State Governments to make rules in respect of minor minerals.―(1) The State Government may, by notification in the Official Gazette, make rules for, regulating the grant of … “minor minerals” means building stones, gravel, ordinary clay, ordinary sand other than sand used for prescribed purposes, and any other mineral which the Central Government may, by notification in the Official Gazette, declare to be a minor mineral;”
The Constitution of India (Legislative Department, Government of India), Seventh Schedule, List II (State List), entry 23 ↗ “Regulation of mines and mineral development subject to the provisions of List I with respect to regulation and development under the control of the Union. … Regulation of mines and mineral development to the extent to which such regulation and development under the control of the Union is declared by Parliament by law to be expedient in the public interest.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q27

Easy

Consider the following:

1.Battery storage
2.Biomass generators
3.Fuel cells
4.Rooftop solar photovoltaic units

How many of the above are considered "Distributed Energy Resources"?

Answer & explanation

Answer: (d) All four

Distributed energy resources (DER) are small generating or storage units placed close to where power is used, usually on the consumer's side of the meter, instead of large central power stations. Rooftop solar, home or grid batteries, small biomass generators and fuel cells are all standard examples.

✓ 1. Battery storage, including electric-vehicle batteries that can send power back to the grid, is listed by Australia's energy market rule-maker (AEMC) as a distributed energy resource.
✓ 2. Small biomass generators running on waste gas or farm and industrial by-products are a DER; the US EPA also lists biomass combustion among distributed generation options.
✓ 3. Fuel cells, run on natural gas, hydrogen or biomass-derived gas, produce electricity on site and are counted as distributed generation.
✓ 4. Rooftop solar PV is the most common DER: power is produced on the building that uses it, and surplus can be fed into the distribution grid.

Remember · DER = small, local generation or storage near the point of use: rooftop solar, small wind, batteries (incl. EVs), biomass generators, fuel cells, CHP units, mini-hydro.

Sources

Australian Energy Market Commission: Distributed energy resources ↗ “Distributed energy resources (DER) refers to often smaller generation units that are located on the consumer’s side of the meter. Examples of distributed energy resources that can be installed include: roof top solar photovoltaic units wind generating units battery storage … biomass generators, which are fuelled with waste gas or industrial and agricultural by-products. open and closed cycle gas turbines reciprocating engines (diesel, oil) hydro and mini-hydro schemes fuel cells.”
US Environmental Protection Agency: Distributed Generation of Electricity and its Environmental Impacts ↗ “Solar photovoltaic panels Wind Hydropower Biomass combustion or cofiring Municipal solid waste incineration Fuel cells fired by natural gas or biomass Reciprocating combustion engines, including backup generators”

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q38

Easy

Recently, the term "pumped-storage hydropower" is actually and appropriately discussed in the context of which one of the following?

Answer & explanation

Answer: (c) Long duration energy storage

Pumped-storage hydropower is a way of storing electricity, not of watering crops. When power is cheap or surplus (for example sunny afternoons with lots of solar), water is pumped from a lower reservoir to an upper one; when demand peaks, it is released back down through turbines. It can hold energy for many hours, which is why it is discussed as long-duration storage for a grid with more solar and wind.

✓ (c) Two reservoirs at different heights work like a giant rechargeable battery; pumped storage is the dominant form of grid-scale energy storage worldwide.
✗ (b) Lift irrigation also pumps water uphill, but only to deliver it to fields; nothing flows back through turbines to generate electricity.
✗ (d) Rainwater harvesting collects and stores rainwater for use or groundwater recharge; it has no power-generation or storage role.

Remember · Pumped-storage hydro = pump water up with surplus power, release it through turbines at peak demand. The biggest grid-scale storage technology; key for integrating solar and wind.

Sources

US Department of Energy, Water Power Technologies Office: Pumped Storage Hydropower ↗ “It is a configuration of two water reservoirs at different elevations that can generate power as water moves down from one to the other (discharge), passing through a turbine. The system also requires power as it pumps water back into the upper reservoir (recharge). … Pumped storage hydropower is the most dominant form of energy storage on the electric grid today. It also plays an important role in bringing more renewable resources onto the grid.”

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q88

Medium

Consider the following statements:

Statement-I: Sumed pipeline is a strategic route for Persian Gulf oil and natural gas shipments to Europe.
Statement-II: Sumed pipeline connects the Red Sea with the Mediterranean Sea.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

The SUMED pipeline runs across Egypt and carries crude oil from the Red Sea to the Mediterranean Sea. Together with the Suez Canal it forms a strategic route for Persian Gulf energy shipments to Europe. The Red Sea-Mediterranean link is exactly what makes it a route to Europe, so Statement-II explains Statement-I.

✓ Statement-I The US Energy Information Administration calls the Suez Canal and the SUMED Pipeline strategic routes for Persian Gulf crude oil, petroleum products and LNG shipments to Europe and North America.
✓ Statement-II The roughly 200-mile SUMED Pipeline carries crude oil northbound through Egypt from the Red Sea to the Mediterranean Sea. It is the only alternative for such crude if ships cannot pass through the Suez Canal, which is why it works as a route to Europe.

Remember · SUMED pipeline: about 200 miles across Egypt, carrying crude oil from the Red Sea to the Mediterranean; the alternative to the Suez Canal for such crude.

Sources

The Suez Canal and SUMED Pipeline are critical chokepoints for oil and natural gas trade (US Energy Information Administration, 2019) ↗ “The Suez Canal and the SUMED Pipeline are strategic routes for Persian Gulf crude oil, petroleum products, and liquefied natural gas (LNG) shipments to Europe and North America. … The 200-mile long SUMED Pipeline transports crude oil northbound through Egypt from the Red Sea to the Mediterranean Sea.”

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2024 · Q97

Medium

Consider the following statements:

Statement-I: Recently, Venezuela has achieved a rapid recovery from its economic crisis and succeeded in preventing its people from fleeing/emigrating to other countries.
Statement-II: Venezuela has the world's largest oil reserves.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (d) Statement-I is incorrect, but Statement-II is correct

Statement-I is wrong: Venezuela has not recovered from its economic crisis, and people have kept leaving, with UNHCR counting nearly 7.9 million Venezuelans abroad in its latest update. Statement-II is right: Venezuela holds the world's largest proven crude oil reserves, about 303 billion barrels in 2023.

✗ Statement-I The US Energy Information Administration says government mismanagement, sanctions and the country's economic crisis have severely hampered even its energy sector. UNHCR reports nearly 7.9 million people who have left Venezuela (December 2025 update), so emigration was not stopped.
✓ Statement-II Venezuela had the world's largest proven crude oil reserves in 2023, about 303 billion barrels or roughly 17% of global reserves. Its production is a small share of world output, which shows that reserves alone did not bring recovery.

Remember · Venezuela: crisis and mass emigration continue (nearly 7.9 million abroad, UNHCR Dec 2025), yet it has the world's largest proven crude oil reserves (about 303 billion barrels, 2023).

Sources

Venezuela country analysis (US Energy Information Administration) ↗ “Venezuela had the world’s largest proven crude oil reserves in 2023 with approximately 303 billion barrels (Figure 5), accounting for approximately 17% of global reserves (Figure 6). … Several factors have severely hampered Venezuela’s energy sector, most notably government mismanagement, international sanctions, and the country’s economic crisis.”
Venezuela situation, UNHCR (updated December 2025) ↗ · reference work “Nearly 7.9 million people have left Venezuela in search of protection and a better life. The majority – more than 6.9 million people – are hosted in Latin American and Caribbean countries.”

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q6

Easy

Ilmenite and rutile, abundantly available in certain coastal tracts of India, are rich sources of which one of the following?

Answer & explanation

Answer: (d) Titanium

Ilmenite and rutile are the main ores of titanium. They occur in the heavy-mineral beach sands of coasts such as those of Kerala and Tamil Nadu, and titanium dioxide made from them is the white pigment used in paints and toothpaste.

✓ (d) Titanium oxide is obtained from the minerals rutile, ilmenite and anatase; ilmenite is found in beach sands along the Kerala and Tamil Nadu coast.
✗ (c) Ilmenite does contain iron (it is an iron-titanium oxide), but it is mined for titanium; India's iron comes from haematite and magnetite ores.
✗ (a) Aluminium is obtained from bauxite, not from ilmenite or rutile.

Remember · Beach-sand minerals: ilmenite and rutile give titanium; monazite gives thorium. Bauxite gives aluminium; haematite and magnetite give iron.

📘 Read it in NCERT: Class 10 Contemporary India – II, Ch 5 (practise this chapter) · Class 12 India: People and Economy, Ch 5 (practise this chapter)

Sources

NCERT Class 10 · Contemporary India – II, Chapter 5 “Most toothpaste are made white with titanium oxide, which comes from minerals called rutile, ilmenite and anatase.”
NCERT Class 12 · India: People and Economy, Chapter 5 “Thorium is mainly obtained from monazite and ilmenite in the beach sands along the coast of Kerala and Tamil Nadu.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q7

Easy

About three-fourths of world's cobalt, a metal required for the manufacture of batteries for electric motor vehicles, is produced by

Answer & explanation

Answer: (c) the Democratic Republic of the Congo

The Democratic Republic of the Congo dominates cobalt mining, supplying roughly 70 per cent or more of the world's mined cobalt, most of it from its copper-cobalt belt in the south-east. Much of this is refined in China and used in rechargeable batteries.

✓ (c) The US Geological Survey reported that Congo (Kinshasa) remained the world's leading source of mined cobalt in 2022, with about 70% of world mine production.
✗ (a) Argentina is known for lithium brines, another battery mineral, not cobalt.
✗ (d) Kazakhstan is the world's largest uranium producer; it is not a major cobalt source.

Remember · Cobalt: DR Congo mines about 70–75% of world output, mostly as a by-product of copper; China leads in refining and battery use.

Sources

US Geological Survey, Mineral Commodity Summaries 2023: Cobalt ↗ “Congo (Kinshasa) continued to be the world’s leading source of mined cobalt, accounting for about 70% of world cobalt mine production.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q11

Easy

Consider the following statements:

Statement-I: India, despite having uranium deposits, depends on coal for most of its electricity production.
Statement-II: Uranium, enriched to the extent of at least 60%, is required for the production of electricity.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (c) Statement-I is correct but Statement-II is incorrect

Coal generates well over two-thirds of India's electricity even though the country has uranium ores, so Statement-I is right. Statement-II is wrong: India's heavy water reactors burn natural (unenriched) uranium and its light water reactors use only low-enriched uranium, nowhere near 60%.

✓ Statement-I Uranium occurs in India, for example in the Dharwar rocks and along the Singhbhum copper belt, but coal-fired plants still supply more than 70% of the electricity generated in the country.
✗ Statement-II Pressurised Heavy Water Reactors, the backbone of India's nuclear power, are fuelled by natural uranium, and Light Water Reactors by low-enriched uranium. Enrichment of 60% or more is not needed to produce electricity.

Remember · Coal: about 70–74% of India's electricity. PHWRs run on natural uranium; LWRs on low-enriched uranium. Power generation does not need highly enriched uranium.

📘 Read it in NCERT: Class 12 India: People and Economy, Ch 5 (practise this chapter)

Sources

PIB (Ministry of Coal), India's Coal Boom ↗ “The coal sector remains a crucial contributor to India’s energy mix, powering over 74% of the country’s electricity and sustaining key industries like steel and cement.”
PIB (Department of Atomic Energy), reactor fuel requirements ↗ “The Pressurised Heavy Water Reactors (PHWRs) are fuelled by Natural Uranium while Light Water Reactors (LWRs) are fuelled by Low Enriched Uranium.”
NCERT Class 12 · India: People and Economy, Chapter 5 “Important minerals used for the generation of nuclear energy are uranium and thorium. Uranium deposits occur in the Dharwar rocks.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q60

Easy

With reference to green hydrogen, consider the following statements:

1.It can be used directly as a fuel for internal combustion.
2.It can be blended with natural gas and used as fuel for heat or power generation.
3.It can be used in the hydrogen fuel cell to run vehicles.

How many of the above statements are correct?

Answer & explanation

Answer: (c) All three

All three statements are correct. Green hydrogen is hydrogen made by splitting water with renewable electricity, and it is chemically the same fuel as any other hydrogen: it can burn in an engine, be mixed into natural gas, or feed a fuel cell.

✓ 1. Hydrogen internal combustion engines are in use: India's pilot projects under the National Green Hydrogen Mission include 22 hydrogen internal-combustion vehicles.
✓ 2. Hydrogen is already being blended into gas networks in India, for example up to 8% by volume in a piped natural gas network in Surat, for use as fuel.
✓ 3. Hydrogen fuel cells power vehicles; the same pilot projects include 15 fuel-cell vehicles, and hydrogen fuel-cell buses already run in Leh and Greater Noida.

Remember · Green hydrogen (made by electrolysis with renewable power) works as engine fuel, as a blend in natural gas, and in fuel cells for vehicles.

Sources

Pilot Projects on Hydrogen Fuelled Buses and Trucks Launched under the National Green Hydrogen Mission (Press Information Bureau, MNRE) ↗ “The vehicles that will be deployed for the trial include 15 hydrogen fuel cell-based vehicles and 22 hydrogen internal combustion engine-based vehicles.”
Status of adoption of green hydrogen in the country (Press Information Bureau, MNRE) ↗ “NTPC Limited has initiated blending of Green Hydrogen up to 8% (vol/vol) in PNG Network at NTPC Kawas Township, Surat, Gujarat from January 2023.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q66

Easy

With reference to coal-based thermal power plants in India, consider the following statements:

1.None of them uses seawater.
2.None of them is set up in water-stressed district.
3.None of them is privately owned.

How many of the above statements are correct?

Answer & explanation

Answer: (d) None

None of the statements is correct, because each says that no coal plant in India does something that at least one plant does. The private Mundra plant in Gujarat uses seawater, and many coal plants stand in water-stressed areas.

✗ 1. The 4,000 MW Mundra Ultra Mega Power Project, a coastal plant, uses seawater; the Central Electricity Authority lists its water source as seawater, with fresh water made by desalination.
✗ 2. A World Resources Institute study, cited in a NITI Aayog-hosted report, found that more than 70% of India's coal power plants are in water-stressed or water-scarce areas.
✗ 3. Mundra UMPP is developed and run by Coastal Gujarat Power Limited, a Tata Power company, so privately owned coal plants exist. Coal capacity is spread across central, state and private owners.

Remember · A single counter-example defeats an 'none of them' claim: Mundra (Tata Power) is a private coal plant using seawater, and most coal plants lie in water-stressed areas.

Sources

Detailed Status of awarded Ultra Mega Power Projects: Mundra UMPP (Central Electricity Authority, Ministry of Power) ↗ “Location : Mundra village in Kutch District, Gujarat Type of Plant : Coastal Name of Developer : Coastal Gujarat Power Limited (Tata Power Company Ltd) … Land : Power Plant - 3068 acres including Ash dyke, colony, corridors etc. Water : Seawater Sweet Water : Sweet Water generation by using Desalination Plant”
Impact of Power Sector Growth on Water Resources (CSTEP study for NITI Aayog) ↗ “According to a World Resources Institute study, more than 70% of India’s coal power plants are located in water stressed or water scarce areas (WRI, 2014).”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2023 · Q76

Medium

Consider the following statements:

Statement-I: According to the United Nations' 'World Water Development Report, 2022', India extracts more than a quarter of the world's groundwater withdrawal each year.
Statement-II: India needs to extract more than a quarter of the world's groundwater each year to satisfy the drinking water and sanitation needs of almost 18% of world's population living in its territory.

Which one of the following is correct in respect of the above statements?

Answer & explanation

Answer: (c) Statement-I is correct but Statement-II is incorrect

Statement-I is correct: India is the world's largest user of groundwater, taking more than a quarter of the global total. Statement-II is wrong because most of that water goes to irrigation, not to drinking water and sanitation.

✓ Statement-I India is the largest groundwater user in the world, drawing an estimated 230 cubic kilometres a year, which is over a quarter of the global total.
✗ Statement-II Agriculture accounts for about 92 per cent of India's groundwater use (NCERT); drinking water and other domestic needs take only a small share. The high extraction is driven by irrigation, so the stated reason is false.

Remember · India draws over a quarter of the world's groundwater, but about nine-tenths of it goes to irrigation, not to drinking water and sanitation.

📘 Read it in NCERT: Class 12 India: People and Economy, Ch 4 (practise this chapter)

Sources

NCERT Class 12 · India: People and Economy, Chapter 4 “Agriculture accounts for most of the surface and groundwater utilisation, it accounts for 89 per cent of the surface water and 92 per cent of the groundwater utilisation.”
World Bank: India Groundwater, a Valuable but Diminishing Resource ↗ “India is the largest user of groundwater in the world. It uses an estimated 230 cubic kilometers of groundwater per year - over a quarter of the global total.”
IGRAC (UNESCO-hosted): India groundwater country profile ↗ · reference work “By 2022, groundwater abstraction was distributed as follows: 87% for irrigation (making agriculture the largest consumer). 11% for domestic use. 2% for industrial use.”

Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q28

Medium

With reference to India, consider the following statements:

1.Monazite is a source of rare earths.
2.Monazite contains thorium.
3.Monazite occurs naturally in the entire Indian coastal sands in India.
4.In India, Government bodies only can process or export monazite.

Which of the statements given above are correct?

Answer & explanation

Answer: (b) 1, 2 and 4 only

Monazite is a phosphate mineral of the beach sands that carries both rare earth elements and thorium. Because of the thorium, it is a 'prescribed substance' under the Atomic Energy Act, 1962, so only government entities licensed by the Department of Atomic Energy handle it. It is concentrated on particular stretches of coast, not all of it.

✓ 1. Monazite is one of the world's principal economic sources of rare earth elements, along with bastnasite and loparite.
✓ 2. Monazite contains thorium; India's thorium comes mainly from monazite in the beach sands of Kerala and Tamil Nadu.
✗ 3. Monazite-bearing sands occur along particular stretches of the peninsular coast (notably Kerala, Tamil Nadu and Odisha), not along the entire Indian coastline.
✓ 4. The Department of Atomic Energy has licensed no private entity to produce, process or export monazite; the public sector IREL (India) Limited handles it.

Remember · Monazite: beach-sand mineral with rare earths + thorium; 'prescribed substance' under the Atomic Energy Act, 1962; handled only by government entity IREL; richest deposits in Kerala.

📘 Read it in NCERT: Class 12 India: People and Economy, Ch 5 (practise this chapter)

Sources

IREL (India) Limited (Department of Atomic Energy): FAQ on rare earths ↗ · reference work “The principal economic sources of rare earths are the minerals bastnasite, monazite, and loparite and the lateritic ion-adsorption clays.”
NCERT Class 12 · India: People and Economy, Chapter 5 “Thorium is mainly obtained from monazite and ilmenite in the beach sands along the coast of Kerala and Tamil Nadu.”
Department of Atomic Energy: Press Release 10/2012 – Export of Monazite from India – Facts ↗ “DAE has not issued any licence to any private entity either for production of monazite, or for its downstream processing for extracting thorium, or the export of either monazite or thorium.”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q72

Hard

In India, what is the role of the Coal Controller’s Organization (CCO)?

1.CCO is the major source of Coal Statistics in Government of India.
2.It monitors progress of development of Captive Coal/Lignite blocks.
3.It hears any objection to the Government’s notification relating to acquisition of coal-bearing areas.
4.It ensures that coal mining companies deliver the coal to end users in the prescribed time.

Select the correct answer using the code given below:

Answer & explanation

Answer: (a) 1, 2 and 3

The Coal Controller's Organisation is a subordinate office of the Ministry of Coal that collects coal statistics, monitors allocated coal blocks and hears objections under the coal-area acquisition law, but it does not police delivery of coal to consumers.

✓ 1. It works under the Collection of Statistics Act and has a Statistics Section; its yearly Coal Directory of India and Provisional Coal Statistics are the standard government source for coal data.
✓ 2. The CCO has a section that monitors allocated coal blocks, including captive coal and lignite blocks.
✓ 3. The Coal Controller hears objections to the Central Government's notification for acquiring coal-bearing land under the Coal Bearing Areas (Acquisition and Development) Act, 1957, and reports to the Centre.
✗ 4. Its listed duties cover grade and quality checks, mining and closure plans, opening permissions and statistics; ensuring that mining companies deliver coal to end users on time is not among them.

Remember · Coal Controller's Organisation: subordinate office of the Ministry of Coal; coal statistics, grade disputes, mining and closure plans, monitoring of coal blocks, and hearings under the 1957 coal-area acquisition Act.

Sources

Ministry of Coal, RTI disclosure: Coal Controller's Organisation functions ↗ “To hear objections to the Central Government Notification relating to acquisition of coal bearing land under Coal Bearing Area (Acquisition and Development) Act, 1957 and to furnish him reports to Central Govt.”
Coal Controller's Organization, About Us (Departments/Sections) ↗ “Statistics Section Monitoring of Coal Block Allocated Section Mine Closure Plan Section Coal Conservation & Development Section Excise Duty Section Technical Section”
Ministry of Coal, Agencies under the Ministry: Coal Controller Organisation ↗ “The Collection of Statistics Act, 1953(32 of 1953) and the Collection of Statistics (Central) Rules, 1959.”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2022 · Q84

Medium

Consider the following statements:

1.Gujarat has the largest solar park in India.
2.Kerala has a fully solar powered International Airport.
3.Goa has the largest floating solar photovoltaic project in India.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (b) 2 only

Only statement 2 is correct: Cochin International Airport in Kerala was the world's first fully solar powered airport. In the exam year the largest solar park was Bhadla in Rajasthan, not a Gujarat park, and Goa did not host India's largest floating solar project.

✗ 1. The Bhadla Solar Park in Rajasthan has a total capacity of 2,245 MW, which made it the largest operating solar park in India when this question was set.
✓ 2. UNEP calls Cochin International Airport, in Kerala, the world's first solar powered airport.
✗ 3. In the exam year (2022) India's largest floating solar project was NTPC's 100 MW plant at Ramagundam in Telangana, which the Ministry of Power announced as fully operational on 1 July 2022. It is not in Goa.
• Since then A Central Electricity Authority report of September 2025 shows Gujarat's planned solar-park capacity (12,150 MW, including the Khavda parks) now above Rajasthan's (11,355 MW). The answer for 2022 is unchanged.

Remember · Bhadla (Rajasthan, 2,245 MW) was India's largest operating solar park in 2022; Cochin Airport (Kerala) is the world's first fully solar powered airport.

Sources

NASA Earthdata, Bhadla Solar Park, India ↗ “The Bhadla Solar Park in Rajasthan, India, which is shown in these true-color reflectance (nadir bidirectional reflectance distribution function [BRDF] adjusted) comparison images, covers an area of 56 square kilometers and has a total capacity of 2,245 megawatts”
UNEP, How trade helped Cochin International become the world’s first solar powered airport ↗ “At Cochin International Airport, the world’s first solar powered airport, switching to solar was not just an environmental decision, but also a business decision.”
PIB, Ministry of Power: India's largest floating solar power project commissioned (1 July 2022) ↗ “NTPC declared Commercial Operation of the final part capacity of 20 MW out of 100 MW Ramagundam Floating Solar PV Project at Ramagundam, Telangana”
Central Electricity Authority, Quarterly Status Report on Development of Solar Parks / UMREPPs (September 2025) ↗ “2. Chhattisgarh 100 0 100 0 100 3. Gujarat 12150 2295 9855 8855 1000”

Question and answer: UPSC's official GS Paper I (2022, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2021 · Q18

Easy

With reference to furnace oil, consider the following statements:

1.It is a product of oil refineries.
2.Some industries use it to generate power.
3.Its use causes sulphur emissions into environment.

Which of the statements given above are correct?

Answer & explanation

Answer: (d) 1, 2 and 3

Furnace oil is a heavy residual fuel left after the lighter fractions are distilled from crude oil in a refinery. Industries burn it in boilers, furnaces and captive power plants, and because it is rich in sulphur, burning it releases sulphur dioxide. All three statements hold.

✓ 1. It is the heavy residue that remains after refineries distil off the lighter products, which is why it is also called residual fuel oil.
✓ 2. Heavy fuel oil is used to produce electric power and for many industrial heating purposes, including captive generation.
✓ 3. Burning oil that contains sulphur emits sulphur dioxide, and furnace oil is among the higher-sulphur fuels, so its use adds SO2 to the air.

Remember · Furnace oil = heavy residual refinery product; burnt in industrial boilers and power units; high sulphur, so a source of SO2.

Sources

US Energy Information Administration, Glossary: Residual fuel oil ↗ “A general classification for the heavier oils, known as No. 5 and No. 6 fuel oils, that remain after the distillate fuel oils and lighter hydrocarbons are distilled away in refinery operations. … No. 6 fuel oil includes Bunker C fuel oil and is used for the production of electric power, space heating, vessel bunkering, and various industrial purposes.”
PIB, Ministry of Environment, Forest and Climate Change: Use of Pet Coke and Furnace Oil in Industries (22 Dec 2017) ↗ “The emission from use of pet coke and furnace oil is expected to contribute in respect of Sulphur Dioxide (SO2) and secondary sulphate component of particulate matter (PM). … Petroleum coke or petcoke and furnace oil which are by-product of crude refining process are also used as fuel by several industries/boilers.”

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q53

Easy

The term ‘West Texas Intermediate’, sometimes found in news, refers to a grade of

Answer & explanation

Answer: (a) Crude oil

West Texas Intermediate (WTI) is a grade of crude oil produced in Texas and southern Oklahoma. It is a reference ("marker") crude whose price is used to price many other crude streams, which is why it appears so often in oil-price news.

✓ (a) WTI is a crude stream from Texas and southern Oklahoma, traded in the US spot market at Cushing, Oklahoma, and used as a pricing benchmark for other crude oils.
✗ (b) Bullion means precious metal, mainly gold or silver, held in bulk; WTI is a grade of oil, not a metal.
✗ (d) Uranium is a nuclear fuel mineral; WTI has nothing to do with it.

Remember · WTI is a US crude oil benchmark, traded in the spot market at Cushing, Oklahoma.

Sources

U.S. Energy Information Administration, Petroleum & Other Liquids: definitions of spot price terms ↗ “A crude stream produced in Texas and southern Oklahoma which serves as a reference or "marker" for pricing a number of other crude streams and which is traded in the domestic spot market at Cushing, Oklahoma.”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q76

Medium

Steel slag can be the material for which of the following?

1.Construction of base road
2.Improvement of agricultural soil
3.Production of cement

Select the correct answer using the code given below:

Answer & explanation

Answer: (d) 1, 2 and 3

Steel slag, the solid waste left when steel is made, is usable in all three ways: as stone-like aggregate in road layers, as a soil conditioner in farming, and as an ingredient in cement.

✓ 1. Processed steel slag replaces natural stone aggregate in roads; CSIR-CRRI has framed guidelines for using it in various road works, and a six-lane highway near Surat was built with it.
✓ 2. The Ministry of Steel lists agriculture as a use, where the slag stands in for soil nutrients and fertilisers, and its website mentions soil conditioning.
✓ 3. The Ministry of Steel names 'green cement' among the uses of steel slag; note that blast-furnace (iron) slag is the type mostly used in cement making today.

Remember · Steel slag is a waste-to-wealth material: road aggregate, soil conditioner, cement ingredient and rail ballast.

Sources

PIB, Ministry of Steel: Steel Minister inaugurates first six-lane highway made of steel slag at Surat (15 June 2022) ↗ “his Ministry is exploring all other options to utilize such materials in road construction, agriculture as a replacement to soil nutrients and fertilizers, ballast for railways and making green cement.”
PIB: Guidelines for Utilization of Steel Slag in Road Construction released (1 July 2024) ↗ “the Ministry of Steel sponsored a major R&D project to CSIR-Central Road Research Institute to facilitate large scale utilization of steel slag as substitute of natural aggregates in road construction.”
Energy and Environment Management in Iron & Steel sector, Ministry of Steel ↗ “The steel industry is finding ways and means to utilize the steel slag in other applications like construction & road making, soil conditioning, rail ballast.”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q79

Easy

Consider the following statements:

1.Coal ash contains arsenic, lead and mercury.
2.Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment.
3.High ash content is observed in Indian coal.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (d) 1, 2 and 3

All three statements are correct: coal ash carries toxic trace metals such as arsenic, lead and mercury, coal-burning power plants emit sulphur dioxide and nitrogen oxides, and Indian coal is high in ash.

✓ 1. Coal and its fly ash hold toxic trace elements; the US Geological Survey names arsenic, selenium, lead and mercury among those tested in fly ash.
✓ 2. CPCB's standards for coal-based thermal power plants set limits for sulphur dioxide and oxides of nitrogen in the flue gas, because burning coal releases both.
✓ 3. The Ministry of Coal states that coal produced in India generally has 25 to 45 per cent ash, against 10 to 20 per cent for imported coal, which is why washing of coal is promoted.

Remember · Coal power means SO2 and NOx in the air and ash laden with arsenic, lead and mercury on the ground; Indian coal is high in ash.

📘 Read it in NCERT: Class 11 Indian Economic Development, Ch 7 (practise this chapter)

Sources

US Geological Survey Fact Sheet 163-97: Radioactive Elements in Coal and Fly Ash ↗ “Standardized tests of the leachability of toxic trace elements such as arsenic, selenium, lead, and mercury from fly ash show that the amounts dissolved are sufficiently low”
CPCB, Thermal Power Plants: Environmental Regulations (emission standards for coal-based plants) ↗ “Sulphur Dioxide ( SO2) 600 mg/Nm3 (Units Smaller than 500MW capacity units) 200 mg/Nm3 (for units having capacity of 500MW and above) Oxides of Nitrogen ( NOx) 600 mg/Nm3”
PIB, Ministry of Coal: High Ash content (3 January 2018) ↗ “Ash content of coal produced in the country is generally 25 to 45 % whereas average ash content of imported coal varies from 10 to 20 %.”
NCERT Class 11 · Indian Economic Development, Chapter 7 “Thermal power plants emit large quantities of carbon dioxide which is a green house gas. It also produces fly ash which, if not used properly, can cause pollution of water bodies, land and other components of the environment.”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q84

Medium

According to India's National Policy on Biofuels, which of the following can be used as raw materials for the production of biofuels?

1.Cassava
2.Damaged wheat grains
3.Groundnut seeds
4.Horse gram
5.Rotten potatoes
6.Sugar beet

Select the correct answer using the code given below:

Answer & explanation

Answer: (a) 1, 2, 5 and 6 only

The National Policy on Biofuels (2018) allows ethanol to be made from cassava, sugar beet, rotten potatoes and damaged food grains such as wheat that are unfit for human consumption. Groundnut and horse gram are edible crops, and the policy's biodiesel route is limited to non-edible oils.

✓ 1. The policy names cassava among the starch-containing materials for bioethanol.
✓ 2. It lists damaged food grains like wheat and broken rice that are unfit for human consumption as ethanol feedstock.
✗ 3. Groundnut is an edible oilseed; the policy's biodiesel feedstock is non-edible vegetable oil, acid oil, used cooking oil or animal fat.
✗ 4. Horse gram is a food pulse and is not named as a biofuel raw material.
✓ 5. Rotten potatoes are listed among the starch-containing materials.
✓ 6. Sugar beet is named among the sugar-containing materials, along with sugar cane and sweet sorghum.

Remember · Biofuel policy feedstock: sugar (cane, beet, sweet sorghum), starch (corn, cassava, rotten potato), unfit food grains for ethanol; non-edible oils and used cooking oil for biodiesel.

Sources

National Policy on Biofuels-2018, Ministry of Petroleum and Natural Gas (Internet Archive copy) ↗ “‘bioethanol’: ethanol produced from biomass such as sugar containing materials, like sugar cane, sugar beet, sweet sorghum etc.; starch containing materials such as corn, cassava, rotten potatoes, algae etc.; … Damaged food grains like wheat, broken rice etc. which are unfit for human consumption, Food grains during surplus phase. … ‘biodiesel’: a methyl or ethyl ester of fatty acids produced from non-edible vegetable oils, acid oil, used cooking oil or animal fat and bio-oil;”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

Prelims 2020 · Q88

Medium

With reference to solar water pumps, consider the following statements:

1.Solar power can be used for running surface pumps and not for submersible pumps.
2.Solar power can be used for running centrifugal pumps and not the ones with piston.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (d) Neither 1 nor 2

Neither statement is correct. A solar panel only supplies electricity, so it can drive any suitable motor-pump: the Ministry of New and Renewable Energy's own specification lists both surface and submersible pump sets for solar water pumping, and piston (positive-displacement) pumps can be powered too.

✗ 1. MNRE's specification says solar photovoltaic water pumping systems may use a surface mono-set or a submersible motor-pump set.
✗ 2. MNRE's PM-KUSUM material names two types of solar water pump, centrifugal and positive displacement, and MNRE has a separate specification for solar pumping systems with positive-displacement pumps. Solar power is not limited to centrifugal pumps.

Remember · Solar pumps are just electric pumps fed by panels: surface or submersible, AC or DC, centrifugal or positive-displacement can all be used.

Sources

Specification and testing procedure for Solar Photovoltaic Water Pumping Systems, Ministry of New and Renewable Energy (updated, February 2023) ↗ “The SPV water pumping systems may use any of the following types of motor pump sets: a) Surface Mono-set b) Submersible motor-pump set.”
PM-KUSUM (MNRE), Type of solar water pumps and different components ↗ “There are namely two general types of pumps used in solar water pumping applications - centrifugal and positive displacement. Both centrifugal and positive displacement pumps can be further classified as:”
MNRE, Annexure A: Solar Water Pumping Systems with Positive Displacement Pump ↗ “The specification covers the technical requirements for Solar Photo Voltaic Water Pumping Systems using positive displacement technology for handling clear cold water covering design qualification s and performance specifications.”

Question and answer: UPSC's official GS Paper I (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

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