According to the World Air Quality Report 2025 released by IQAir: Loni (Uttar Pradesh) is the most polluted city in the world. The report analysed data from 9,446 cities across 143 countries. Loni recorded a PM2.5 concentration of 112.5 µg/m³, over 22 times the WHO safe limit (5 µg/m³). Delhi ranked 4th globally and remains the most polluted capital city.
Global Rankings: Most Polluted Cities (2025)
The top 10 polluted cities globally include:
- Loni (India)
- Hotan (China)
- Byrnihat (India)
- Delhi (India)
- Faisalabad (Pakistan)
- Rahim Yar Khan (Pakistan)
- Ghaziabad (India)
- Lahore (Pakistan)
- Sukkur (Pakistan)
- Ula (India)
Notably, 5 out of top 10 cities are from India.
Key Global Findings
- Pakistan is the most polluted country, followed by Bangladesh, Tajikistan, Chad, Congo, and India (6th)
- 25 most polluted cities are concentrated in India, Pakistan, and China
- Only 14% of global cities met WHO PM2.5 guideline, down from 17% last year
- Only 13 countries/territories met WHO standards (e.g., Iceland, Australia, Estonia)
Environmental Drivers:
- Wildfires significantly worsened air quality globally
- Biomass emissions (Europe & Canada) contributed ~1,380 megatons of carbon
- Canada recorded its second-worst wildfire season, impacting North America and Europe
India-Specific Concerns
India is the 6th most polluted country in terms of PM2.5 levels India continues to face severe air pollution challenges:
- Major sources: vehicular emissions, industrial pollution, crop residue burning, construction dust
- Winter months see extreme pollution due to temperature inversion, trapping pollutants near the surface
- Cities in the Indo-Gangetic Plain are particularly vulnerable
Despite measures under the National Clean Air Programme (NCAP) (2019) targeting 40% reduction in PM levels by 2025–26, progress remains slow due to weak enforcement and coordination. Recent interventions like cloud seeding in Delhi have shown limited success.
Why is Loni the Most Polluted?
The severe pollution in Loni is due to a combination of geographical and anthropogenic factors:
- Located in the Indo-Gangetic Plain, prone to pollution trapping
- Temperature inversion in winters prevents dispersion of pollutants
- High emissions from:
- Vehicular traffic
- Brick kilns and metal industries
- Unregulated industrial clusters using dirty fuels
This creates a persistent pollution hotspot.
Global Comparison and Trends
- The United States saw PM2.5 rise to 7.3 µg/m³;
- Most polluted city: El Paso
- Cleanest major city: Seattle (4.5 µg/m³)
- Europe saw mixed trends:
- 23 countries recorded increases
- Transboundary pollution (wildfires, Saharan dust) impacted air quality
- China has shown improvement due to strict long-term pollution control policies, contrasting with India’s slower progress.