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.”

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.

A Pakistani province declared a health emergency Friday due to smog and imposed a shutdown in two major cities. Smog has choked Punjab for weeks, sickening nearly 2 million people and shrouding vast swathes of the province in a toxic haze.

From banning tuk-tuks and barbecues to demolishing old brick kilns, Pakistan's government is pushing a series of measures to fight record-breaking smog.