New Delhi, Nov. 24 -- Early this month, while New Delhi struggled with severe air pollution, Chinese embassy spokesperson Yu Jing took to X to compare the air pollution crises in both countries, and offered to share Beijing's experience in improving its air quality. The post's context was the annual episode of north Indian skies turning sickly yellow, which sparked rare protests by citizens of Delhi this year.

Just over a decade ago, China was in the same boat. Its megacities Beijing and Shanghai regularly had PM2.5 levels more than 10-20 times the safe level recommended by the World Health Organization (WHO). PM2.5 is fine particulate matter that can penetrate the lung barrier and enter the blood system. The WHO says its average annual ...