In a new global ranking, IQAir, a Swiss firm, has listed the top regions in the world, including cities and entire countries that are losing their respective battles against air pollution.
The findings come from IQAir’s 2025 World Air Quality Report, released on March 24.
And once again, India has found itself ranking higher on a list that is far from ideal.
WHICH IS THE MOST POLLUTED CITY IN THE WORLD?
A small town on the outskirts of Ghaziabad, Uttar Pradesh, has the unfortunate distinction of being the most polluted city on the planet in 2025.
Loni recorded an annual average PM2.5 concentration of 112.5 micrograms per cubic metre, a nearly 23% jump from 2024 and more than 22 times the safe limit set by the World Health Organisation (WHO).
PM2.5 refers to tiny particles in the air smaller than 2.5 micrometres. These particles are so fine that they can enter your lungs and bloodstream directly.
Long-term exposure to them is linked to asthma, heart disease and even cancer. The WHO recommends an annual average of no more than 5 micrograms per cubic metre.
Loni sits in the National Capital Region (NCR), a region notorious for trapped air.
The area is ringed by industrial units, brick kilns, and heavy-vehicle traffic. Furthermore, in winter, cool stagnant air acts like a lid, locking pollution close to the ground.
Stubble burning in Punjab and Haryana contributes up to 60% of air pollution in northern India’s colder months, making an already bad situation dramatically worse each October to January.
HOW POLLUTED IS INDIA?
While Loni grabbed the top spot, the country as a whole did not fare that well either.
Byrnihat in Meghalaya came third globally in terms of air pollution and Delhi ranked fourth.
New Delhi also topped the list of the world’s most polluted capital cities.
India ranked sixth amongst the most polluted countries with pollution levels nearly 10 times the WHO guideline. The alarming levels in Delhi, however, represented a marginal 3% dip from 2024, though experts deemed the decline statistically insignificant.
India was home to three of the four most polluted cities in the world, and all 25 cities in the global bottom tier were located in India, Pakistan, or China.
HOW POLLUTED IS THE WORLD?
Apart from India’s battle with pollution, the picture worldwide is also grim.
Only 14% of cities globally met the WHO’s PM2.5 standard in 2025, down from 17% the previous year.
Pakistan ranked as the world’s most polluted country, with PM2.5 levels, 13 times the WHO limit. Wildfires, made worse by climate change, pushed pollution across North America and into Europe, while Southeast Asian nations like Laos and Cambodia showed improvement thanks to wetter La Nina weather patterns.
At the end, the annual report pointed to the fact that clean air remains a privilege, not a given, especially for millions of Indians. For millions more, it is still a distant reality.
