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National Air Quality Index
In one line: India's National Air Quality Index, launched on 17 October 2014, turns readings of eight pollutants into a single number from 0 to 500.
The pollutants and bands
The eight are PM10, PM2.5, nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, ammonia and lead. The six bands are good (0 to 50), satisfactory (51 to 100), moderate (101 to 200), poor (201 to 300), very poor (301 to 400) and severe (401 to 500).
The rules
Each pollutant gets a sub-index; the worst sub-index is the overall AQI. At least three pollutants must be measured, one of them PM2.5 or PM10. Most pollutants use 24-hour averages; carbon monoxide and ozone use 8-hour averages.
Where to go next
- National Ambient Air Quality Standards
- Commission for Air Quality Management
National Air Quality Index in the news
- Delhi's winter curbs kick in as CAQM orders pre-emptive NCR curbs for 5 to 20 November 1 November 2026
How India scores air quality and which pollutants count
- Delhi's September AQI hits a five-year low even as PM2.5 and PM10 levels rose 2 October 2026
How eight pollutants become one number.
Previous-year questions on this
- 2021 · GS3 · 10 marks Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What…
- 2020 · GS3 · 15 marks What are the key features of the National Clean Air Programme (NCAP) initiated by the Government of India?
- 2016 · Prelims 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…