Minimalist IAS
Environment & ecology

Prelims · Environment & ecology · 40 questions

Pollution & waste

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

Pollution & waste questions per year: 2016: 1, 2017: 2, 2018: 1, 2019: 5, 2020: 2, 2021: 6, 2022: 3, 2023: 2, 2024: 4, 2025: 4, 2026: 0 Asked in 10 of 11 years · most in 2021 (6)

Practising Environment & ecology? Take it as timed sets of 25 →

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

हमारे देश के शहरों में वायु गुणता सूचकांक (Air Quality Index) का परिकलन करने में साधारणतया निम्नलिखित वायुमंडलीय गैसों में से किनको विचार में लिया जाता है?

  1. 1.कार्बन डाइऑक्साइड
  2. 2.कार्बन मोनोक्साइड
  3. 3.नाइट्रोजन डाइऑक्साइड
  4. 4.सल्फर डाइऑक्साइड
  5. 5.मेथैन

नीचे दिए गए कूट का प्रयोग कर सही उत्तर चुनिए।

Read this question in English

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?

1. Carbon dioxide

2. Carbon monoxide

3. Nitrogen dioxide

4. Sulfur dioxide

5. Methane

Select the correct answer using the code given below.

(a) 1, 2 and 3 only · (b) 2, 3 and 4 only · (c) 1, 4 and 5 only · (d) 1, 2, 3, 4 and 5

उत्तर और व्याख्या · explanation in English

Answer: (b) केवल 2, 3 और 4

Carbon monoxide, nitrogen dioxide and sulfur dioxide are used in India's National Air Quality Index; carbon dioxide and methane are not. The index is built from eight pollutants for which short-term air quality standards exist: PM10, PM2.5, NO2, SO2, CO, ozone, ammonia and lead.

  • ✗ 1. Carbon dioxide is a greenhouse gas, not one of the eight pollutants in the National AQI.
  • ✓ 2. Carbon monoxide (CO) is one of the eight AQI pollutants.
  • ✓ 3. Nitrogen dioxide (NO2) is one of the eight AQI pollutants.
  • ✓ 4. Sulfur dioxide (SO2) is one of the eight AQI pollutants.
  • ✗ 5. Methane is a greenhouse gas and is not among the eight pollutants used for the AQI.

Remember · National AQI pollutants: PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb. No CO2 and no methane.

📘 Read it in NCERT: Class 8 Curiosity, Ch 8 (practise this chapter)

Sources

  • About National Air Quality Index (Central Pollution Control Board) ↗ “AQ sub-index and health breakpoints are evolved for eight pollutants (PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Pb) for which short-term (upto 24-hours) National Ambient Air Quality Standards are prescribed.”
  • NCERT Class 8 · Curiosity, Chapter 8 “The major pollutants present in the air are particulate matter (dust, soot) and gases like carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. The air quality index (AQI) is a tool used to describe the air quality.”

Question and answer: UPSC's official GS Paper I (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·

The Syllabus X-Ray of this topic

2 of its 7 sub-topics are Core

2 Core · 2 High · 2 Steady · 1 Rare

  • Core #13Air pollution & air-quality standards · 11 questions
  • Core #60Solid, plastic & e-waste · 6 questions
  • HighSoil, noise & heavy-metal pollution · 5 questions
  • HighWater pollution & treatment · 3 questions

The X-Ray ranks all 928 sub-topics of the UPSC syllabus by what UPSC has asked since 2016. The 60 Prelims Core sub-topics are behind 51% of Prelims questions.

See the whole X-Ray →

The same topic in Mains

Read it in NCERT