The chief minister of Pakistan’s most populous province called for “climate diplomacy” with neighbour and arch-rival India to combat smog ahead of the winter months, which are accompanied by dangerous levels of pollution in both nations.

“We should talk to them, this is called climate diplomacy. We should do it with India,” said Chief Minister Maryam Nawaz Sharif, adding the two nations needed to coordinate actions to temper toxic smog, which winds carry across the border.

Relations between India and Pakistan have gone through periods of thaw but have been largely frozen since they downgraded diplomatic ties in tit-for-tat moves in 2019.

When cooler temperatures take hold, pollution spirals. The Pakistani city of Lahore and India’s capital Delhi are among the most polluted cities in the world.

Air quality deteriorates in cooler months, as temperature inversion traps pollution closer to the ground, packing hospital wards with patients with respiratory problems.

Rising air pollution can cut life expectancy by more than five years per person in South Asia, one of the world’s most polluted regions, according to a report published last year which flagged the growing burden of hazardous air on health.

India’s foreign minister will visit Pakistan next week to attend the Shanghai Cooperation Organisation summit, the first such visit in nearly a decade. However India’s government has ruled out discussions of bilateral relations during the visit.