Air quality in Lahore reached hazardous levels this week, while other cities in South Asia also battle toxic pollution.

One doctor compared breathing in Pakistan's toxic air to smoking "dozens of cigarettes a day" as Lahore is the world's most polluted city this week.

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.

Authorities in Pakistan’s Punjab have declared a health emergency in the country's east due to increasing smog as more than 2 million people complained of respiratory illnesses. All educational institutions have been shut,

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