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.

Pakistan's most populated province of Punjab on Wednesday ordered schools closed in smog-hit main cities, shifting them to online learning until November 17, as the country battles record air pollution.

But Wednesday's index score for Lahore fell short of last week's unprecedented score of 1900, which had exceeded recommended levels by more than 120 times, prompting closure of primary schools