Bengaluru: India ranked as the world’s sixth most-polluted country in 2025 based on PM2.5 levels, according to the World Air Quality Report released by IQAir. The country recorded a population-weighted average PM2.5 concentration of 48.9 µg/m³, a marginal drop from 50.6 µg/m³ in 2024, though experts said the decline is not statistically significant. The World Health Organization recommends an annual limit of 5 µg/m³.
India was also home to the world’s most polluted city, with Loni in Ghaziabad recording an annual average PM2.5 concentration of 112.5 µg/m³—over 22 times the WHO guideline and nearly 23% higher than in 2024. Among global capitals, New Delhi remained the most polluted, with an average of 82.2 µg/m³, followed by Dhaka and Dushanbe.
The report analysed air quality data from 9,446 cities across 143 countries, drawing from more than 40,000 monitoring stations operated by governments, institutions and citizen scientists. Globally, only 13 countries met the WHO’s annual PM2.5 guideline, with most located in Latin America and the Caribbean.
Central and South Asia continued to record the highest pollution levels, accounting for 17 of the world’s 20 most polluted cities. Of 358 cities analysed in the region, 71 reported PM2.5 levels exceeding 50 µg/m³—more than ten times the WHO standard.
India dominated the global pollution rankings, with several cities among the worst affected. Byrnihat in Meghalaya ranked third with 101.1 µg/m³, followed by Delhi at 99.6 µg/m³, Ghaziabad at 89.2 µg/m³, and Ula (Birnagar) in West Bengal at 86.6 µg/m³. The cleanest city globally was Nieuwoudtville in South Africa, with an annual average of just 1.0 µg/m³.
Globally, 54 countries saw an increase in PM2.5 levels in 2025, while 75 recorded declines and two remained unchanged. Pakistan topped the list as the most polluted country with an average PM2.5 level of 67.3 µg/m³, followed by Bangladesh, Tajikistan, Chad and the Democratic Republic of Congo, with India ranking sixth.
Despite an 8% annual decline in PM2.5 levels in Delhi, the city continued to face severe pollution spikes driven by dust storms, seasonal smog and regional factors. A major dust storm in April led to a 15% surge in pollution, while December saw PM2.5 levels rise by 44% in Delhi and by an average of 62% in neighbouring cities in Uttar Pradesh.
Key contributors to India’s air pollution remained vehicular emissions, industrial activity, crop residue burning and construction dust. The report highlighted gaps in policy implementation, noting that while the National Clean Air Programme aims to reduce pollution by 40% by 2025–26, most funding has been directed towards road dust, with limited focus on industrial emissions and biomass burning.
Experts stressed the need for stricter enforcement of emission norms, expansion of real-time monitoring, and a faster transition to renewable energy. Reducing dependence on fossil fuels, curbing crop burning and improving transport systems were identified as critical steps to achieve long-term improvements in air quality.