Pakistan world’s most polluted country, followed by Bangladesh; India at 6th spot: Report
The 2025 edition of the report, published by Swiss air quality technology company IQAir, is based on analysis of data from monitoring stations in 9,446 cities in 143 countries, territories and territories.
The data was obtained from more than 40,000 regulatory monitoring stations and low-cost sensors around the world managed by a wide range of contributors, including government agencies, universities, non-profit organizations, private companies, and engaged citizen scientists.
Among the most polluted countries in the world, China ranks 20th, the USA ranks 120th and the UK ranks 110th.
According to the report, only 13 countries or territories (French Polynesia, Puerto Rico, US Virgin Islands, Barbados, New Caledonia, Iceland, Bermuda, Reunion, Andorra, Australia, Grenada, Panama and Estonia) met the World Health Organization (WHO) annual average PM2.5 guideline.
“Out of 143 countries or territories, 130 (91 percent) exceeded the WHO annual average PM2.5 guideline value. The five most polluted countries were Pakistan, Bangladesh, Tajikistan, Chad and the Democratic Republic of Congo. All of the world’s 25 most polluted cities were located in India, Pakistan and China; India was home to three of the four most polluted cities,” the report said.
Nieuwoudtville, South Africa became the cleanest city in the world with an average annual PM2.5 concentration of 1.0 g/m³. Among the cities, Loni in Uttar Pradesh is the most polluted city, followed by Hotan in China and Byrnihat in Meghalaya, India. Delhi is ranked fourth, followed by Faisalabad in Pakistan.
“Wildfire activity in 2025 severely impacted regions that have historically experienced relatively low levels of PM2.5. As a result, only 14 percent of global cities met WHO’s annual PM2.5 guidance in 2025, compared to 17 percent in 2024.”
“This downward trend is a stark reminder that maintaining clean air requires active management and a proactive strategy, regardless of historical performance,” the report said.
Maintaining clean air is a long-term commitment to incremental improvement rather than a single policy target or annual target concentration achieved, it said.
“But for children, the effects of exposure to air pollution can last a lifetime; respiratory damage incurred during their formative years is often irreversible. As the demographic group with the least agency in these environmental changes, children are forced to bear the permanent health costs of air quality they did not choose,” the report said.
