A dense cloud of smog has enveloped the Indian city of Delhi and surrounding areas, sending the air quality index to hazardous highs, making it difficult for residents to breathe and disrupting public life.

So far, government officials have shut down schools, restricted the usage of polluting vehicles and paused construction activity.

“The situation arising out of air pollution in the City is extremely worrying,” Delhi’s Lieutenant Governor Vinai Kumar Saxena said in a Friday post on X, formerly Twitter.

Good or satisfactory air quality corresponds to an index somewhere between zero and 100. The air quality index in Delhi on Monday was roughly 450, according to India’s Central Pollution Control Board.