India has ranked sixth among the most polluted countries in the world, while Delhi has been placed fourth among the most polluted cities globally, according to the World Air Quality Report 2025. Loni, a city in Ghaziabad district of Uttar Pradesh, approximately 20 kilometres from Delhi, recorded the worst levels of fine particulate matter of any city in the world. The eighth edition of the report, published by IQAir, a Swiss air quality technology company, analysed data from monitoring stations across 9,446 cities in 143 countries, regions and territories. Pakistan topped the list of most polluted countries, followed by Bangladesh, Tajikistan, Chad and Congo, with India at sixth place.
Five Indian cities featured among the ten most polluted in the world.
- Loni in Ghaziabad district of Uttar Pradesh (topped the global list)
- Byrnihat in Ri-Bhoi district of Meghalaya
- Delhi
- Ghaziabad in Ghaziabad district of Uttar Pradesh
- Ula in North 24 Parganas district, West Bengal
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The report noted that the world’s 25 most polluted cities were all located in India, Pakistan and China, with India home to three of the four most polluted. Loni recorded an annual average PM2.5 concentration of 112.5 µg/m³, a nearly 23 per cent increase from 2024 and more than 22 times the WHO guideline.
Globally, 54 countries saw a rise in annual average PM2.5 levels compared to the previous year, while 75 recorded a drop, two remained unchanged, and 12 were newly represented in this year’s dataset.
Only 14 per cent of global cities met the WHO annual PM2.5 guideline of 5 µg/m³, down from 17 per cent the previous year. Just thirteen countries and territories met the WHO standard, including Australia, Iceland, Estonia, Andorra, Panama and Grenada, among others.
“This open, transparent data is an essential tool for holding polluters accountable and securing a healthy environment for everyone,” the report said.
