Pakistan’s second-largest city of Lahore has been shrouded in a dense layer of hazardous smog for much of November, intensifying health concerns for its residents. The pollution peaked on November 14. Data from the Swiss air-quality monitoring organisation, IQAir, revealed the city’s Air Quality Index (AQI) skyrocketed to an unusually high and hazardous 1,110, and tiny particulate matter, or PM2.5, reached a staggering 632 micrograms per cubic meter of air.

In Punjab, where Lahore is located, authorities declared a health emergency during the month, closed schools and held university classes online. They imposed a ban on construction to try to mitigate the impact of the pollution.

The annual pollution in Lahore not only started earlier than usual, but it was also more severe. PM2.5 concentrations frequently surpassed hazardous thresholds — the highest recorded in the past five years.