Air pollution remains a serious health risk in India, reducing life expectancy by an estimated 5.2 years. Four cities in neighbouring Pakistan and one in China are among the world’s top 20 polluted cities. The World Air Quality Report 2024 by Swiss air quality technology company IQAir said Delhi remains the most polluted capital city globally. The Indian cities in the top 20 most polluted cities are Byrnihat, Delhi, Punjab’s Mullanpur, Faridabad, Loni, Gurugram, Ganganagar, Greater Noida, Bhiwadi, Muzaffarnagar, Hanumangarh and Noida. About 1.5 million deaths in India every year from 2009 to 2019 were potentially linked to long-term exposure to PM2.5 pollution, according to a Lancet Planetary Health study published last year. The high level of pollution is due to emissions from local factories, including distilleries, iron and steel plants, the report said. The report said 35 per cent of the Indian cities reported annual PM1.5 levels exceeding 10 times the WHO limit of 5 micrograms per cubic metre.