In the Punjab region of Pakistan, record-high air pollution levels have triggered hundreds of hospitalizations, school closures and stay-at-home orders, as cities and towns remain shrouded in a thick, toxic smog.

On the outskirts of Lahore, the region’s biggest city of 13 million residents, the Air Quality Index was the worst ever recorded on Sunday, over six times higher than the level classified as “hazardous” by the U.S. EPA.

Over 900 people, including children and elderly residents, were hospitalized on Tuesday alone due to the pollution, according to government officials.