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.

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,