The Delhi High Court on Tuesday asked Punjab, Haryana, Delhi and Rajasthan governments to inform it about the actions taken against stubble burning, reported ANI. The court’s directions come as pollution rose to dangerous levels in the National Capital Region.

However, the High Court bench said that “stubble burning may be the visible villain but there are other contributory factors too”.

Delhi Chief Minister Arvind Kejriwal also blamed crop burning in adjoining states for the rising pollution levels in the NCR. He asked Education Minister Manish Sisodia to consider closing schools for a few days as the NCR woke up to thick smog on Tuesday. A public health emergency was declared after the air quality dropped to the “severe” category.

Kejriwal compared the Capital with a gas chamber, and called for a permanent solution to crop burning in adjoining states. “Every year, during this time of the year, Delhi becomes a gas chamber for almost a month,” the chief minister said on Twitter.

The alarming level of pollution also affected train and flight services, according to the Hindustan Times. While 33 trains were running late by over three hours, at least seven flights were delayed. One flight from Lucknow was diverted to Jaipur.

The Environment Pollution (Prevention and Control) Authority suggested that the parking fees in the NCR be increased four times, reported The Indian Express. It also asked the Delhi Metro to slash fares during lean hours for at least 10 days, and add more coaches to the trains.

The authority also asked the Delhi government to consider reintroducing the odd-even policy if the pollution did not reduce. The odd-even scheme prohibits vehicles from plying on roads based on the last digit of their registration numbers. Only vehicles with numbers ending with an odd digit can ply on odd dates while others are allowed only on even dates. However, all cars are allowed to ply on Sundays.