Smog shuts city down as even schools close

On the streets of Pakistan's second biggest city, smog stings eyes and burns throats. Inside homes, few people can afford air purifiers to limit the damage of toxic particles that seep through doors and windows.

Lahore - a city of 14 million people stuffed with factories on the border with India - regularly ranks among the world's most polluted cities, but it has hit record levels this month.

Schools have closed in the main cities of Punjab province, of which Lahore is the capital, until Sunday in a bid to lower children's exposure to the pollution, especially during the morning commute when it is often at its highest.

"The children are constantly coughing, they have constant allergies," said Rafia Iqbal, a 38-year-old primary school teacher in the city that borders India.

"In schools we saw that most of the children were falling sick." Her husband Muhammad Safdar, a 41-year-old advertising professional, said the level of pollution "is making daily living impossible".