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Environment & EcologyEasyAsked in: SSC MTS · 7 August 2019, Shift 1

Which of the following synthetic chemical is responsible for ozone layer depletion?

  1. A.Polyvinylchloride
  2. B.Chlorofluorocarbons
  3. C.Biopolymer
  4. D.Methanol

Correct answer

B. Chlorofluorocarbons

Explanation

The correct answer is B, Chlorofluorocarbons. CFCs release chlorine in the stratosphere, and that chlorine destroys ozone.

CFCs were used as refrigerants, in aerosol sprays and in foam. They are stable near the ground, so they drift up to the stratosphere, where ultraviolet light breaks them and frees chlorine atoms. One chlorine atom can destroy thousands of ozone molecules in a chain reaction, which is how the ozone hole over Antarctica formed. The Montreal Protocol of 1987 phased CFCs out, and 16 September is observed as World Ozone Day.

Option A, polyvinylchloride, is a plastic and a waste problem, but it does not reach the stratosphere. Option C, biopolymer, means a natural polymer such as cellulose or starch and is harmless to ozone. Option D, methanol, is an alcohol used as a fuel and solvent and has no role in ozone loss.

Exam tip: ozone killers are CFCs, halons and carbon tetrachloride; the Montreal Protocol, 1987, controls them.

Practice Questions

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Q2.Environment & EcologyAsked in: CDS · CDS-I 2019, GKMedium

Which one of the following statements about the National Green Tribunal is not correct?

  1. A.It was set up in the year 2010.
  2. B.It is involved in effective and expeditious disposal of cases relating to environmental protection and conservation of forests.
  3. C.It may consider giving relief and compensation for damages to persons and property.
  4. D.It is bound by the procedures laid down under the Code of Civil Procedure, 1908.
Show answer
Correct answer: D. It is bound by the procedures laid down under the Code of Civil Procedure, 1908.

The National Green Tribunal is not bound by the Code of Civil Procedure; it is guided by the principles of natural justice.

Q3.Environment & EcologyAsked in: CDS · CDS-I 2018, GKHard

Consider the following statements about National Wildlife Action Plan (NWAP) of India for 2017-2031:

1. This is the Third National Wildlife Action Plan.

2. The NWAP is unique as this is the first time India has recognized the concerns relating to climate change impact on wildlife.

3. The NWAP has ten components.

Which of the statements given above is/are correct?

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

The plan for 2017-2031 is India's third National Wildlife Action Plan and the first to deal with the impact of climate change on wildlife, but it has five components, not ten.