https://www.theguardian.com/world/20...nt-be-measured
Concern about north India’s air quality crisis is usually most acute after the Hindu festival of Diwali in autumn, when hundreds of thousands of Indians release firecrackers that combine with existing pollutants to form a poisonous haze over the region that persists for months until temperatures cool.Meteorologists said the presence of a layer of dust across the city is also trapping heat, sending temperatures soaring in excess of 40C.