Lahore air stays hazardous as smog forecast to worsen Monday

Lahore's air remained in the hazardous range through the first week of November, with an average Air Quality Index of 268 for 1-7 November and a peak of 335 on 2 November, Express News reported, citing the Pakistan Air Quality Initiative. UrduPoint reported that smog could worsen on Monday, pointing to Diwali fireworks and polluted winds arriving from India, and said pollution was expected to stay at its highest until 10am on 9 November.

Five of the seven days were classed extremely unhealthy and two hazardous, the Express News report said. PM2.5, the fine particles that reach deep into the lungs, averaged 215.5 micrograms per cubic metre over the week, about 14 times the World Health Organization guideline of 15 micrograms.

The week was Lahore's third worst for air pollution in nine years of records, the report said, and PM2.5 levels were 25 percent higher than in the same period last year. Low night temperatures and weak winds kept the particles suspended over the city.

Fires added to the load. An average of 54.8 fire incidents a day were recorded in the city across the week. Crop residue burning, vehicle and other local emissions, dust and winter weather were listed among the likely causes. The analysis drew on city monitoring, NASA's fire detection system and smoke maps from the US agency NOAA.

On 2 November, NASA satellites detected 488 fires within 300 kilometres of Lahore, 204 of them inside a 100-kilometre radius, but the report said it could not confirm that the smoke had reached the city.

Smog Rank, a separate monitoring project cited by Express News, put Lahore's PM2.5 average at 210.1 micrograms per cubic metre over the previous seven days against 65.2 micrograms over the past year, about 3.2 times higher, and at 282.1 micrograms on 2 November. The city's yearly average is 4.3 times the WHO limit, and November and December are its worst months, at 237.7 micrograms.

UrduPoint attributed the expected worsening to Diwali fireworks and air crossing from India. The Express News report examined wind direction for the same week and found no day on which the share of winds from the Indian side reached 25 percent or more. Days with a higher share of such winds averaged an AQI of 160, against 187 on the other days, it said, adding that wind trajectory analysis does not by itself establish where the pollution came from.