Delhi air quality slips to severe levels after Diwali fireworks

Air quality in the Indian capital deteriorated sharply on Monday after fireworks were set off during Diwali celebrations in violation of court orders.

Data from the Central Pollution Control Board showed Delhi's Air Quality Index at 370 around 9 am, in the 'very poor' band. In several parts of the city of 20 million people, readings crossed 400, entering the 'severe' category.

Earlier this month the Supreme Court had ruled that only certified low-pollution fireworks could be used, and only during specified hours over the Diwali weekend. Residents nevertheless reported fireworks going off late into the night in Delhi and in the financial capital Mumbai, and the area around India Gate, close to government offices and parliament, lay shrouded in smog.

The Swiss air quality monitoring firm IQAir ranked Delhi among the most polluted major cities in the world following the celebrations.

Authorities had urged residents to celebrate responsibly, pointing to the capital region's long-running struggle with winter pollution, when smoke, vehicle emissions and still air combine to trap pollutants close to the ground.