Pakistan's province of Punjab set up a "smog war room" to tackle severe pollution, officials said, as poor air quality turned its capital of Lahore into the world's most polluted city and forced the closure of some educational institutions.

The Punjab government has ordered a one-week closure of primary schools in Lahore, affecting classes from nursery to Grade 5.

Dangerously poor air quality on Monday forced Pakistani authorities in the cultural capital of Lahore to close primary schools for a week, government officials said, after the air-quality index hit a record high over the weekend.

Pakistan's second-largest city has closed schools for the week, not that students will be able to go outside. The air pollution in Lahore is now second-worst in the world only to New Delhi, India, according to the Swiss outfit IQAir,