Smog has enveloped much of Pakistan and India, causing road accidents and respiratory problems.
Pakistani meteorologist Mohammad Hanif said Sunday that the pollution, caused by the burning of crops and emissions from factories and brick kilns in Pakistan and neighbouring India, was expected to linger until the middle of the month.
Some private schools in the Indian capital, New Delhi, have suspended sports and outdoor activities.
India's Supreme Court banned the sale of fireworks in New Delhi ahead of last month's Hindu Diwali festival to try to curb air pollution in the notoriously smoggy city.
Though reports said air quality was better than last year, pollution levels in the capital hit 18 times the healthy limit a night after the festival, as many ignored the ban.