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.

Delhi remains the most polluted capital city globally, while India ranked fifth in 2024, down from third in 2023.

The Indian cities in the world's top 20 most polluted cities are Byrnihat, Delhi, Punjab's Mullanpur, Faridabad, Loni, Gurugram, Ganganagar, Greater Noida, Bhiwadi, Muzaffarnagar, Hanumangarh and Noida.

In Delhi, pollution worsened, with PM2.5 levels rising from 102.4 micrograms per cubic metre in 2023 to 108.3 micrograms per cubic metre in 2024.

Air pollution remains a significant health burden in India, reducing life expectancy by an estimated 5.2 years

The 7 countries that met the WHO guideline of 5 μg/m3 are Australia, the Bahamas, Barbados, Estonia, Grenada, Iceland, and New Zealand.

India ranks as the world's 5th most polluted country, with Byrnihat being the most polluted city and Delhi the most polluted capital. Air pollution has cut life expectancy by 5.2 years, causing 1.5 million deaths annually.

Delhi remains the most polluted capital city globally, while India ranked fifth in 2024, down from third in 2023.