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.

Pakistani officials say dangerously poor air quality has forced the provincial government in Lahore to close primary schools for a week.

A toxic cloud of smog has swept over Pakistan and India, causing one of Pakistan's major cities to put schools on lockdown. On Sunday, the capital of the Punjab region of Pakistan, Lahore, held the real-time top spot as the world's most polluted city,