Lahore recorded an air quality index (AQI) of 458 on Friday morning, placing it first among the world's major cities for air pollution, according to data from Swiss monitoring group IQAir. Multan recorded 719, with several other cities in Punjab also showing very high readings as pre-winter smog settled over the region.

IQAir ranked New Delhi second among major cities with an AQI of 244 and Kolkata third with 235. Within Punjab, Kahna Nau recorded 655 and Kasur 462 on the provincial index. The Punjab Air Quality Index put Lahore at 430 at 7am, 70 points higher than the previous day, with Kasur first in the province and Lahore second.

Local readings were higher still in some neighbourhoods: CERP Office at 611, Barki Road Paragon at 609, Allama Iqbal Town at 583 and Raiwind at 511, while Kahna Nau, Multan Road and Safari Park in Lahore reached 500. Daily Pakistan reported Paragon Society at 548 and the FC College area at 508.

Health advice as smog thickens

Express News reported that the pollution levels pose serious health risks to residents of Lahore and several other Punjab cities. Citizens have been advised to avoid unnecessary outdoor trips and to wear masks when going out. Those who work or travel outdoors are most exposed to the high readings. The Meteorological Department forecast 17 to 30 degrees Celsius in Lahore over the next 24 hours.

Officials report later improvement

Later on Friday, provincial officials said Lahore's air quality had improved, recording a reading of 149, down from 312 the previous day. Senior provincial minister Maryam Aurangzeb attributed the decline to enforcement, continuous monitoring and changes in weather conditions and wind speed. Delhi, meanwhile, ordered schools to offer online classes as its AQI reached 382.