Consider the following statements: Statement-I. Circular economy reduces the emissions of greenhouse gases. Statement-II. Circular economy reduces the use of raw materials as inputs. Statement-III. Circular economy reduces wastage in the production process. Which one of the following is correct in respect of the above statements?

(d) Neither Statement II nor Statement III is correct

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?

(d) Neither Statement II nor Statement III is correct

Consider the following statements: Statement I. At the 28th United Nations Climate Change Conference (COP28), India refrained from signing the 'Declaration on Climate and Health'. Statement II. The COP28 Declaration on Climate and Health is a binding declaration; and if signed, it becomes mandatory to decarbonize health sector. Statement III. If India's health sector is decarbonized, the resilience of its health-care system may be compromised. Which one of the following is correct in respect of the above statements?

(d) Neither Statement II nor Statement III is correct

Consider the following statements: Statement I. Article 6 of the Paris Agreement on climate change is frequently discussed in global discussions on sustainable development and climate change. Statement II. Article 6 of the Paris Agreement on climate change sets out the principles of carbon markets. Statement III. Article 6 of the Paris Agreement on climate change intends to promote inter-country non-market strategies to reach their climate targets. Which one of the following is correct in respect of the above statements?

(d) Neither Statement II nor Statement III is correct

With reference to ‘Direct Air Capture’, an emerging technology, which of the following statements is/are correct? I. It can be used as a way of carbon sequestration. II. It can be a valuable approach for plastic production and in food processing. III. In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel. Select the correct answer using the code given below.

(d) None of the above statements is correct

Environment & ecology

Prelims · Environment & ecology · 53 questions

Climate change & agreements

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

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UPSC syllabus: “General issues on Environmental ecology, Bio-diversity and Climate Change - that do not require subject specialization.” See the full syllabus →

Prelims 2025 · Q9

Easy

Consider the following statements:

Statement-I: Circular economy reduces the emissions of greenhouse gases.
Statement-II: Circular economy reduces the use of raw materials as inputs.
Statement-III: Circular economy reduces wastage in the production process.

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

Answer & explanation

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

A circular economy keeps materials in use through reuse, repair and recycling instead of the 'take–make–dispose' model. Using fewer fresh raw materials cuts the energy spent extracting and processing them, and cutting waste cuts the emissions from producing and disposing of it, so both II and III explain the fall in greenhouse gas emissions.

✓ Statement-I The European Parliament lists a reduction in total annual greenhouse gas emissions among the benefits of a circular economy.
✓ Statement-II Reusing and recycling products slows the use of natural resources, so fewer virgin raw materials are needed; this lowers emissions from mining and processing.
✓ Statement-III Better design and efficient production reduce waste and the energy and resources consumed, which also lowers emissions.

Remember · Circular economy = reduce, reuse, repair, recycle. Fewer raw materials and less waste mean less energy use and lower greenhouse gas emissions.

Sources

European Parliament, Circular economy: definition, importance and benefits (2023) ↗ “Parliament wants Europeans to switch to a circular economy by using raw materials more efficiently and reducing waste. … Another benefit from the circular economy is a reduction in total annual greenhouse gas emissions. Creating more efficient and sustainable products from the start would help to reduce energy and resource consumption”

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 · Q29

Easy

Consider the following statements:

I.Without the atmosphere, temperature would be well below freezing point everywhere on the Earth's surface.
II.Heat absorbed and trapped by the atmosphere maintains our planet's average temperature.
III.Atmosphere's gases, like carbon dioxide, are particularly good at absorbing and trapping radiation.

Which of the statements given above are correct?

Answer & explanation

Answer: (c) I, II and III

All three describe the natural greenhouse effect. The Earth's surface re-radiates sunlight as infrared heat; gases such as carbon dioxide, methane and water vapour absorb much of it, which keeps the global average near 15°C. Remove that blanket and the surface would be about 33°C colder, below freezing.

✓ I Without the atmosphere's greenhouse effect the average surface temperature would fall by roughly 33°C, from about 15°C to around −18°C, too cold for life.
✓ II The heat that the atmosphere absorbs and traps is what holds the planet's average temperature at a life-supporting level.
✓ III Carbon dioxide, methane and water vapour absorb the infrared heat re-radiated by the surface and stop it escaping to space.

Remember · Natural greenhouse effect: CO2, CH4, water vapour trap outgoing infrared; keeps Earth ≈ 15°C instead of ≈ −18°C (a 33°C difference).

📘 Read it in NCERT: Class 9 Exploration, Ch 13 (practise this chapter)

Sources

NCERT Class 9 · Exploration, Chapter 13 “Greenhouse gases like CO2, CH4 and water vapour absorb this re-radiated heat, preventing it from escaping into space. Without the atmosphere, the Earth would be too cold for life to survive.”
NASA Science: What is the greenhouse effect? ↗ “If carbon dioxide were removed, the terrestrial greenhouse effect would collapse, and Earth's surface temperature would drop significantly, by approximately 33°C (59°F). … Part of what makes Earth so amenable is its natural greenhouse effect, which maintains an average temperature of 15 ° C (59 ° F) .”

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 · Q32

Hard

Consider the following statements:

Statement I: At the 28th United Nations Climate Change Conference (COP28), India refrained from signing the 'Declaration on Climate and Health'.
Statement II: The COP28 Declaration on Climate and Health is a binding declaration; and if signed, it becomes mandatory to decarbonize health sector.
Statement III: If India's health sector is decarbonized, the resilience of its health-care system may be compromised.

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

Answer & explanation

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

India is not among the signatories of the COP28 UAE Declaration on Climate and Health (Dubai, December 2023); the list on the COP28 site goes from Iceland straight to Indonesia. The declaration is a political declaration whose commitments are made 'according to our national circumstances', so Statement II is wrong.

✓ Statement I India did not sign: the list of signatories on the COP28 site names 151 signatories, including the European Union, and India is not among them. The declaration was launched on COP28's inaugural Health Day, 3 December 2023.
✗ Statement II The declaration is not a mandate: its signatories commit to better integrating health into climate policy and to promoting steps such as assessing health-system emissions and developing action plans and decarbonisation targets, all 'according to our national circumstances'. Signing does not make decarbonising the health sector mandatory.
✓ Statement III UPSC's official key treats this as correct; we could not confirm India's stated reason from an official source, so we do not explain it here.

Remember · COP28 (Dubai, 2023) Declaration on Climate and Health: first Health Day at a COP, 151 signatories; India is not on the list. Commitments are 'according to our national circumstances', not mandatory.

Sources

COP28 UAE Presidency: COP28 UAE Declaration on Climate and Health ↗ · reference work “To achieve these aims - according to our national circumstances - we commit to pursuing the better integration of health considerations into our climate policy processes, … Promoting steps to curb emissions and reduce waste in the health sector, such as by assessing the greenhouse gas emissions of health systems, and developing action plans, nationally determined decarbonization targets, … 54. Hungary 55. Iceland 56. Indonesia 57. Iran 58. Iraq 59. Ireland 60. Israel 61. Italy”
WHO: COP28 UAE Declaration on climate and health ↗ “In a historic milestone marking the inaugural Health Day at the 28th UN Climate Change Conference (COP28), global leaders united in endorsing the health and climate change declaration,”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

Prelims 2025 · Q34

Medium

Consider the following statements:

Statement I: Article 6 of the Paris Agreement on climate change is frequently discussed in global discussions on sustainable development and climate change.
Statement II: Article 6 of the Paris Agreement on climate change sets out the principles of carbon markets.
Statement III: Article 6 of the Paris Agreement on climate change intends to promote inter-country non-market strategies to reach their climate targets.

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

Answer & explanation

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

Article 6 is the Paris Agreement's provision on voluntary cooperation between countries. It covers market approaches (carbon-market rules) and non-market approaches, so II and III are both true. Because it is the Agreement's route for cross-border carbon trading and other cooperation, it features regularly in climate and sustainable-development talks, which is what Statement I says; II and III explain that.

✓ Statement I Article 6 deals with international cooperation on carbon markets and non-market approaches, so it is a regular subject in climate and sustainable-development negotiations.
✓ Statement II Article 6.2 lays down the principles for voluntary cooperative approaches that transfer mitigation outcomes between countries (sustainable development, environmental integrity, transparency, robust accounting), and 6.4 sets up a mechanism for emission reductions.
✓ Statement III Article 6.8 recognises non-market approaches that help countries implement their nationally determined contributions, and 6.9 defines a framework to promote them.

Remember · Article 6 of the Paris Agreement: 6.2 = voluntary cooperative approaches (internationally transferred mitigation outcomes), 6.4 = a mitigation mechanism under COP/CMA authority, 6.8 = non-market approaches.

Sources

UNFCCC: Paris Agreement (English text), Article 6.2 ↗ “Parties shall, where engaging on a voluntary basis in cooperative approaches that involve the use of internationally transferred mitigation outcomes towards nationally determined contributions, promote sustainable development and ensure environmental integrity and transparency … Parties recognize the importance of integrated, holistic and balanced non-market approaches being available to Parties to assist in the implementation of their nationally determined contributions, in the context of sustainable development and poverty eradication”

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 · Q35

Easy

Which one of the following launched the ‘Nature Solutions Finance Hub for Asia and the Pacific’?

Answer & explanation

Answer: (a) The Asian Development Bank (ADB)

The Asian Development Bank (ADB) launched the Nature Solutions Finance Hub for Asia and the Pacific at COP28 in Dubai on 4 December 2023. It aims to attract at least $2 billion into investment programmes that include nature-based solutions, especially from capital markets and private capital.

✓ (a) ADB's own news release calls it 'ADB's Nature Solutions Finance Hub for Asia and the Pacific' and says ADB launched it at COP28.
✗ (b) The Asian Infrastructure Investment Bank is a separate regional lender and is not the launcher of this hub, though it too works in the Asia-Pacific.
✗ (d) The IBRD (World Bank) did not launch this hub; the initiative belongs to ADB, as its own release says.

Remember · Nature Solutions Finance Hub for Asia and the Pacific: launched by ADB at COP28 (Dubai, 4 December 2023), aiming to draw at least $2 billion into nature-based solutions.

Sources

ADB news release: ADB and Partners Launch Nature Financing Initiative for Asia and the Pacific (4 December 2023) ↗ · reference work “The Asian Development Bank (ADB) today launched a Nature Solutions Finance Hub for Asia and the Pacific at COP28 which aims to attract at least $2 billion into investment programs that incorporate nature-based solutions”

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 · Q36

Medium

With reference to ‘Direct Air Capture’, an emerging technology, which of the following statements is/are correct?

I.It can be used as a way of carbon sequestration.
II.It can be a valuable approach for plastic production and in food processing.
III.In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel.

Select the correct answer using the code given below.

Answer & explanation

Answer: (c) I, II and III

Direct air capture (DAC) pulls CO2 straight out of ambient air. The captured CO2 can be stored underground, which removes it from the atmosphere, or used as a carbon feedstock for products such as food and beverages, chemicals and some plastics, and, combined with hydrogen, for synthetic aviation fuel. All three statements describe real uses.

✓ I Capturing CO2 from the air and storing it permanently removes it from the atmosphere; this is carbon removal by sequestration.
✓ II Air-captured CO2 can serve as a climate-neutral feedstock for a range of products, from food and beverages to chemicals, and some plastics are among the CO2-based products.
✓ III Air-captured CO2 combined with hydrogen is used to make synthetic hydrocarbon fuels, notably for aviation.

Remember · Direct air capture takes CO2 from ambient air: store it (carbon removal) or use it (food and beverages, chemicals, plastics, and synthetic fuels made with hydrogen).

Sources

IEA: Direct Air Capture: A key technology for net zero (2022), Abstract ↗ · reference work “Capturing CO2 directly from the air and permanently storing it removes the CO2 from the atmosphere, providing a way to balance emissions that are difficult to avoid … Air-captured CO2 can also be used as a climate-neutral feedstock to produce a range of products, from synthetic aviation fuels to food and beverages. … Early commercial efforts to develop synthetic aviation fuels using air-captured CO2 and hydrogen have started, reflecting the important role that these fuels could play”

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 · Q64

Medium

The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35 °C. Which of the following statements best reflect(s) the implication of the above-said report?

I.Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.
II.The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.

Select the correct answer using the code given below.

Answer & explanation

Answer: (c) Both I and II

UPSC's official answer: (c) · the answer UPSC accepted, and the one that counts in the exam

What we believe is right: (b)

Statement II is the direct implication. Wet-bulb temperature combines heat and humidity; 'as the wet-bulb temperature approaches your core temperature, you lose the ability to cool down' (NASA), and the World Bank treats 35 °C as the point where heat waves 'break the human survivability limit'.
Statement I is not an implication of that warning. The World Bank report (Climate Investment Opportunities in India's Cooling Sector, 2022) projects the 35 °C threshold for 'the Chota Nagpur Plateau and North-Eastern India', and nowhere mentions floods, tropical cyclones, droughts or peninsular India.
A warning about heat stress does not imply a forecast of flooding and cyclones for a different region, so a strict reading accepts II only: (b).
UPSC's key accepts both, presumably reading the warning as one face of climate change over India whose other faces are floods, cyclones and drought.

UPSC's key accepts both statements; the report itself supports only II, giving (b). In the exam, when the stem says 'best reflect(s) the implication' and 'Both' is offered, UPSC has accepted a broad climate-impact statement alongside the direct one; but know what the report actually says.

World Bank (2022): Climate Investment Opportunities in India's Cooling Sector, the warning ↗“Soon India could become one of the first places in the world to experience heat waves that break the human survivability limit”
World Bank (2022): Climate Investment Opportunities in India's Cooling Sector, where 35 °C is projected ↗“climate models project that these temperatures could exceed the survivability threshold (that is, 35°C) at a few locations in the Chota Nagpur Plateau and North-Eastern India under future climate scenarios”
NASA Science: Too Hot to Handle, how wet-bulb temperature stops the body cooling ↗“But as the wet-bulb temperature approaches your core temperature, you lose the ability to cool down.”

This box is Minimalist IAS's analysis, with its sources; it does not change UPSC's answer.

UPSC's key accepts both statements. Statement II is the direct implication: wet-bulb temperature combines heat and humidity, and as it nears the body's core temperature sweat can no longer evaporate fast enough to shed heat, so survival itself is threatened. Statement I is counted as the wider implication: the key reads the warning as a sign of a climate system under stress over India, whose other faces are flooding, tropical cyclones and drought.

✓ I UPSC's key counts this as an implication. The report's warning of routine 35 °C wet-bulb readings signals a warmer, moister atmosphere over India; the key reads the hazards that go with such warming — heavier rain and flooding, stronger cyclones on the peninsula's coasts, longer dry spells — as part of what the warning implies.
✓ II Wet-bulb temperature combines heat and humidity. Near the body's core temperature, sweat cannot evaporate enough to cool the body (NASA), and the World Bank treats 35 °C as that survivability threshold.

Remember · Wet-bulb temperature combines heat and humidity. Near 35 °C sweat cannot cool the body, so survival is at risk; the World Bank flagged India as an early case.

Sources

World Bank (2022): Climate Investment Opportunities in India's Cooling Sector ↗ “Soon India could become one of the first places in the world to experience heat waves that break the human survivability limit … climate models project that these temperatures could exceed the survivability threshold (that is, 35°C) at a few locations in the Chota Nagpur Plateau and North-Eastern India under future climate scenarios”
NASA Science: Too Hot to Handle: How Climate Change May Make Some Places Too Hot to Live ↗ “As long as the wet-bulb temperature is well below your skin temperature, your body can release heat to your surroundings through radiation and sweating. But as the wet-bulb temperature approaches your core temperature, you lose the ability to cool down.”

Question and answer: UPSC's official GS Paper I (2025, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink ·

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