Record high air pollution has forced the authorities in Pakistan’s second-largest city of Lahore to close primary schools for a week and issue work-from-home mandates.

The country’s cultural capital held the top spot on a real-time list of the world’s most polluted cities on Sunday after recording its highest-ever pollution reading of 1900 near the Pakistan-India border, based on data released by the provincial government and Swiss group IQAir. The concentration of PM 2.5, or tiny particulate matter, in the air, approached 450 – a level considered hazardous.

The government has shut primary schools for a week, advising parents to ensure children wear masks, said a minister of Punjab province, Marriyum Aurangzeb, during a news conference, as a thick blanket of smog enveloped the city of 14 million people.

Citizens have been urged to stay indoors, keep doors and windows shut, and avoid unnecessary travel, she said, adding that hospitals had been given smog counters and construction work had been banned in certain areas.

Fifty percent of employees must also work from home as part of a “green lockdown” in the city, the government said, adding that barbecuing food without filters was banned and motorised rickshaws restricted. Wedding halls must close at 10pm and artificial rain is likely to be used to combat the pollution.

Toxic smog has sickened tens of thousands of people, mainly children and the elderly, since last month when the air quality started worsening in Lahore, the capital of eastern Punjab province – which was known as a city of gardens during the Mughal era from the 16th to the 19th centuries. But rapid urbanisation and a surging population growth have left little room for greenery.