Islamabad, Nov 3 (IANS): As residents of Lahore gasp for breath under persistent smog with the air quality index mark surpassing 1,000 once again on Sunday, making it the most polluted city in the world, the Punjab province government on Sunday announced the closure of all primary schools in the city in the coming week.

As per a notification, schools, both public and private, up to Class 5 will remain closed from November 4 to 9 in the light of the smog situation, Geo TV reported.

For days, the 14 million people of the city have been affected by smog, a mix of fog and pollutants caused by diesel fumes, and smoke from seasonal agricultural burning, amid the cooling effect of the approaching winter season.

As per the Swiss air quality monitor, IQAir, the level of deadly PM2.5 pollutants peaked at 613, which is 122.6 times higher than the level considered unhealthy by the World Health Organisation.

The AQI, which measures a range of pollutants, spiked to 1,073 at 10 a.m., surpassing Saturday's "unprecedented" 1,067.

At one point, the AQI reached 1,194 before dipping down to 766 by noon.

Multiple measures by the provincial government, including a "green lockdown" in the city's air pollution hotspots, imposed on October 30, have had no effect.

Addressing a press conference in Lahore, Punjab's Senior Minister Marriyum Aurangzeb, who holds multiple portfolios including environment protection and climate change, said two more regions in Lahore would be marked for green lockdown next week as the pollution level was not dying down.

Given the pattern of prevailing winds, the province would continue to face spiking pollution levels in the morning for the next week, she said.

"Playgroup to primary group classes will remain off while strict vigilance will be kept on children above primary classes," she said, adding wearing masks should be made mandatory at government and private schools.

She also warned that construction sites would be permanently shut down if guidelines were flouted

Marriyum Aurangzeb emphasised that smog could not be controlled without talking to India, as most of the pollution was coming from across the border.

“Though local factors are also behind the smog, however, the winds coming from the neighbouring country are affecting Lahore the most. The citizens are inhaling methane gas," she said.

She said smog had spread to Islamabad as well.