The Indian capital topped charts as the world’s most-polluted city after firecrackers from Diwali celebrations pushed air quality to dangerous levels.

A thick layer of smog shrouded New Delhi on Friday, after revelers celebrating Diwali, the Hindu festival of lights, flouted a ban on firecrackers.

The air quality index stood at over 345 shortly after dawn, according to Swiss firm IQ Air, driving pollution in the sprawling Indian capital to “hazardous.” It also put New Delhi at the top of a real-time list as the world’s most-polluted city, above Lahore in neighboring Pakistan.

In recent years, authorities in New Delhi have outlawed the use and sale of traditional firecrackers during Diwali and have urged people to instead celebrate the light festival with more environmentally friendly options.