Why this matters now
Air pollution is a recurring current-affairs and GS-3 topic — the pollutants, AQI, sources (including stubble burning) and the NCAP. Indian cities frequently top global pollution rankings.
Pollutants and sources
Key pollutants include particulate matter (PM2.5 and PM10), sulphur dioxide (SO₂), nitrogen oxides (NOₓ), carbon monoxide (CO) and ground-level ozone. Sources span vehicles, industry, power plants, construction dust, biomass burning and crop-residue (stubble) burning. PM2.5 is especially harmful as it penetrates deep into the lungs.
The Air Quality Index (AQI)
The Air Quality Index (AQI) converts pollutant concentrations into a single, colour-coded number from “Good” to “Severe,” making air quality easy to communicate. It is monitored by the Central Pollution Control Board (CPCB).
Effects
Air pollution causes respiratory and cardiovascular diseases, premature deaths, reduced crop yields and lower visibility, and contributes to climate change. It imposes a heavy health and economic burden, especially on cities and vulnerable groups.
NCAP and measures
The National Clean Air Programme (NCAP) is a national strategy to reduce particulate pollution in non-attainment cities with time-bound targets. Other measures include BS-VI fuel/vehicle norms, promotion of electric vehicles and clean cooking (LPG), dust control, and tackling stubble burning, under the Air (Prevention and Control of Pollution) Act, 1981.
UPSC angle
Know the key pollutants (esp. PM2.5/PM10), the AQI and CPCB, the major sources (vehicles/industry/stubble), and the NCAP + Air Act 1981 + BS-VI as policy responses.
Frequently asked questions
What are the main air pollutants?
Particulate matter (PM2.5, PM10), sulphur dioxide, nitrogen oxides, carbon monoxide and ground-level ozone.
What is the Air Quality Index (AQI)?
A colour-coded index that converts pollutant levels into a single number from “Good” to “Severe” to communicate air quality, monitored by the CPCB.
What is the NCAP?
The National Clean Air Programme — a national strategy with time-bound targets to cut particulate pollution in non-attainment cities.
Why is PM2.5 especially dangerous?
Because these fine particles penetrate deep into the lungs and bloodstream, causing serious respiratory and cardiovascular harm.