Pakistan ’s smog situation has gone from bad to worse as air pollution rose to a record in Lahore. Sensors tracked by the Swiss monitor IQAir recorded an air quality index of 1,300 in the country’s second-largest city at 5 p.m. local time, the highest this year and well beyond a level of 50 that is deemed safe.

The crisis has prompted a flurry of responses from local authorities, as the country grapples with its most severe air pollution event in years. According to several Pakistani media reports the Punjab Provincial Disaster Management Authority had declared smog a “calamity” and instituted emergency measures.

Pakistan’s second-largest city of Lahore will close primary schools for a week after seeing “unprecedented” pollution levels, government authorities have said. For days, the city of 14 million people has been enveloped by smog, a mix of fog and pollutants caused by low-grade diesel fumes, smoke from seasonal agricultural burning and winter cooling.

The air quality index is alarmingly high in Pakistan and India. This week, smog has drastically reduced visibility, obscuring views of landmarks such as the Taj Mahal in Agra. Consequently, many flights have been delayed.