ISLAMABAD (AP) — Smog has enveloped much of Pakistan and neighboring India, causing highway accidents and respiratory problems, and forcing many residents to stay home, officials said Saturday.

Pakistani meteorologist Mohammad Hanif said the pollution, caused by dust, the burning of crops, and emissions from factories and brick kilns in Pakistan and neighboring India, was expected to linger until the middle of the month. He advised people to wear face masks to protect themselves from respiratory ailments.

Mohammad Arshad, a highway police official, said at least 10 people were killed and 25 injured in road accidents linked to poor visibility in various parts of the Punjab province since Monday. Authorities have advised people to limit road travel.

Average air pollution in Pakistan's major cities is about four times higher than the World Health Organization limits.

Similar problems have been reported in the Indian capital, New Delhi, where air quality was rated "very poor" on Saturday. Some private schools in New Delhi have suspended sports and outdoor activities.

India's Supreme Court banned the sale of firecrackers 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 the night after the festival, as many dodged the ban.

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Associated Press Writer Ashok Sharma in New Delhi, India contributed to this story.