Pakistan's Punjab province declared a health emergency due to toxic smog on Friday, banning construction, shutting schools for another week and moving universities online, while hundreds of thousands of Muslims prayed for rain and forgiveness.

The government of Pakistan’s most polluted province has launched a new policy to address a protracted smog crisis, after the world’s worst air shuttered schools and saw 900 people seek hospital treatment in a single day.

The U.N. children’s agency is warning that the health of 11 million children in Pakistan’s eastern Punjab province is in danger because of air pollution that experts say has become a fifth season in recent years.

Air quality deteriorated to hazardous levels in New Delhi on Wednesday as toxic smog blanketed India, leaving residents of the capital complaining of “apocalyptic” scenes. The crisis also affected neighbouring Pakistan,