Pollution in the Vietnamese capital of Hanoi, home to almost 9 million people, reflects the environmental cost of the Southeast Asian nation’s explosive growth.

All but one of the world’s top 20 most polluted cities last year were in Asia, a new study shows.

All but one of the world’s top 20 most polluted cities last year were in Asia, with the majority of these cities – 13 – in India, the world’s most populous country.

Six out the world’s 10 most polluted cities are in India, while California has the worst air pollution in North America, a new report shows.

(CNN) — 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 ...

Chad in central Africa is the world’s most polluted country, while California has the worst air pollution in North America, according to an IQAir report.

(CNN) — 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 ...

(CNN) — 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 ...