How many pollutants are included in India’s National Air Quality Index framework?

Explanation

India’s National Air Quality Index framework includes eight pollutants: PM₁₀, PM₂.₅, NO₂, SO₂, CO, O₃, NH₃ and Pb. The overall index is governed by the highest applicable pollutant sub-index. Listing eight pollutants in the framework does not mean every station measures all eight continuously.