2016 GS Paper I, all questions

UPSC Prelims 2016 · GS Paper I

Question 86: Environment and Ecology

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

  1. 1.Carbon dioxide
  2. 2.Carbon monoxide
  3. 3.Nitrogen dioxide
  4. 4.Sulfur dioxide
  5. 5.Methane

Select the correct answer using the code given below.

a1, 2 and 3 only
b2, 3 and 4 only
c1, 4 and 5 only
d1, 2, 3, 4 and 5

AnswerUPSC’s answer is (b).

India's National Air Quality Index covers eight pollutants: PM10, PM2.5, nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, ammonia and lead. Carbon dioxide and methane are greenhouse gases but are not part of the AQI. Of the five gases listed, carbon monoxide, nitrogen dioxide and sulphur dioxide are the ones used.

  • 1. Carbon dioxide is not an AQI pollutant.
  • 2. Carbon monoxide is an AQI pollutant.
  • 3. Nitrogen dioxide is an AQI pollutant.
  • 4. Sulphur dioxide is an AQI pollutant.
  • 5. Methane is not an AQI pollutant.

How you could have got this

  1. If you were sure statement 1 is not correct, (a), (c) and (d) go: each of them includes 1.

    What you needed to know: Carbon dioxide is not an AQI pollutant.

Only (b) is left. You didn’t need statements 2, 3, 4 or 5.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong
  • (a) Carbon dioxide is not used in the AQI.
  • (b) Right: carbon monoxide, nitrogen dioxide and sulphur dioxide are used.
  • (c) Carbon dioxide and methane are not used in the AQI.
  • (d) Carbon dioxide and methane are not used, so 'all five' fails.

Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2016, General Studies Paper I, Series A. The paper on upsc.gov.in.