All but one of the world’s top 20 most polluted cities last year were in Asia, a new study shows. The majority of these cities – 13 – are in the world’s most populous country, India, where booming economic growth is fired largely by coal and where hundreds of millions live in traffic-clogged and congested megacities .

Despite an improvement in 2024, India again dominated global rankings for the cities with the most dangerous particle smog while Chad was the most polluted country, according to a report published Tuesday.