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.
Answer & explanation
Answer: (b) 2, 3 and 4 only
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). ·