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.

With smog intensity escalating in Lahore at the end of October, affecting its 13 million residents, the Punjab government imposed a “green lockdown” and set up a “smog war room.”

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,

The United Nations Children's Fund (UNICEF) has raised concerns about the health risks facing 11 million children in Pakistan's eastern Punjab province due to worsening air pollution, which experts say has effectively become a "fifth season" in recent years.