Pakistan's Punjab declared a health emergency due to toxic smog on Friday, banning construction, shutting schools for another week and moving universities online, with a three-day lockdown possible, the province's senior minister said on Friday.

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.”

Pakistan's most populated province of Punjab on Friday extended school closures in smog-hit major cities by a week, as the country battles record