Diwali fireworks

Angry Indians tweet after Diwali fireworks choke Delhi

Levels of PM10 particulates, considered hazardous to health, rose to 999 micrograms per cubic metre, way above the safe limit of 100.

Authorities had warned that Delhi was in for a polluted Diwali due to factors like humidity and wind speed.

Fire crackers are regularly set off during Diwali but worsen air quality.

Delhi's local government announced last week that it would install air purifiers near roads in an effort to cut the effects of air pollution.