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Environment & EcologyMediumAsked in: UPSC CAPF · CAPF 2025, Paper I

Which one among the following is not a greenhouse gas?

  1. A.Sulphur dioxide
  2. B.Methane
  3. C.Nitrous oxide
  4. D.Fluorinated gas

Correct answer

A. Sulphur dioxide

Explanation

The correct answer is A, Sulphur dioxide. Sulphur dioxide is an air pollutant, not one of the greenhouse gases; in fact the sulphate particles it forms reflect sunlight and have a slight cooling effect.

Greenhouse gases absorb the infrared heat given off by the Earth's surface and warm the lower atmosphere. The Kyoto Protocol listed six of them: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride, with nitrogen trifluoride added later. The last four are the fluorinated gases, which are few in quantity but very powerful and long-lived. Sulphur dioxide comes mainly from burning coal and from volcanoes; it causes acid rain and respiratory illness, but it is not counted as a greenhouse gas.

B is wrong because methane, from paddy fields, cattle and landfills, is a strong greenhouse gas. C is wrong because nitrous oxide, mostly from fertilisers, is a long-lived greenhouse gas. D is wrong because fluorinated gases such as HFCs and SF6 are among the most potent greenhouse gases.

Exam tip: Kyoto gases — CO2, CH4, N2O, HFCs, PFCs, SF6; SO2 causes acid rain, not warming.

Practice Questions

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Q1.Environment & EcologyAsked in: UPSC Civil Services · CSE Prelims 2018, GS Paper IMedium

With reference to organic farming in India, consider the following statements :

1. 'The National Programme for Organic Production' (NPOP) is operated under the guidelines and directions of the Union Ministry of Rural Development.

2. 'The Agricultural and Processed Food Products Export Development Authority' (APEDA) functions as the Secretariat for the implementation of NPOP.

3. Sikkim has become India's first fully organic State.

Which of the statements given above is/are correct?

  1. A.1 and 2 only
  2. B.2 and 3 only
  3. C.3 only
  4. D.1, 2 and 3
Show answer
Correct answer: B. 2 and 3 only

NPOP is run by the Ministry of Commerce and Industry, not Rural Development, while the statements about APEDA and Sikkim are correct.

Q2.Environment & EcologyAsked in: UPSC Civil Services · CSE Prelims 2018, GS Paper IHard

Consider the following statements :

1. The definition of "Critical Wildlife Habitat" is incorporated in the Forest Rights Act, 2006.

2. For the first time in India, Baigas have been given Habitat Rights.

3. Union Ministry of Environment, Forest and Climate Change officially decides and declares Habitat Rights for Primitive and Vulnerable Tribal Groups in any part of India.

Which of the statements given above is/are correct ?

  1. A.1 and 2 only
  2. B.2 and 3 only
  3. C.3 only
  4. D.1, 2 and 3
Show answer
Correct answer: A. 1 and 2 only

The Forest Rights Act defines critical wildlife habitat, and the Baigas were the first community to receive habitat rights, but the Environment Ministry does not grant those rights.

Q4.Environment & EcologyAsked in: UPSC Civil Services · CSE Prelims 2022, GS Paper IEasy

Consider the following :

1. Carbon monoxide

2. Nitrogen oxide

3. Ozone

4. Sulphur dioxide

Excess of which of the above in the environment is/are cause(s) of acid rain ?

  1. A.1, 2 and 3
  2. B.2 and 4 only
  3. C.4 only
  4. D.1, 3 and 4
Show answer
Correct answer: B. 2 and 4 only

Nitrogen oxides and sulphur dioxide are the two gases that turn rain acidic. When coal and oil burn in power plants, factories and vehicles, they release sulphur dioxide and nitrogen oxides into the air.