Delhi world’s most polluted capital again; pollution cuts life expectancy in India by 5 years: Report

India is the fifth most polluted country in the world, with an average Air Quality Index (AQI) of 50.6 μg/m3 – 10 times higher than the World Health Organization’s (WHO) annual PM2.5 guideline value of 5 μg/m3. In 2023, it was the third most polluted country.

“Air pollution remains a significant health burden in India, reducing life expectancy by an estimated 5.2 years,” it said.

Most Polluted Cities in the World

The report has relied on data from over 40,000 air quality monitoring stations at 8,954 locations in 138 countries, territories and regions. It was analysed by IQAir’s air quality scientists.

These are the key findings of the report:

• Only 17% of global cities met WHO air pollution guidelines. Out of the 138 countries and regions, 126 (91.3%) exceeded the WHO annual PM2.5 guideline value of 5 μg/m3.
• Byrnihat, India was the most polluted metropolitan area in 2024, with an annual average PM2.5 concentration of 128.2 μg/m3. Central and South Asia were home to the top seven most polluted cities in the world. India was home to six of the nine most polluted global cities.
• The most polluted major city in the United States was Los Angeles, California. Ontario, California was the most polluted city in the US.
• PM2.5 concentrations decreased in every country in Southeast Asia, though trans-boundary haze and lingering El Niño conditions remain major factors.
• In Africa, the scarcity of real-time, publicly accessible air quality monitoring data is so severe that there is only one monitoring station for every 3.7 million people.

While Delhi has seen a slight improvement, the report said, the NCR region is still heavily polluted.

“India saw a 7% decline in PM2.5 concentrations in 2024, averaging 50.6 µg/m³ compared to 54.4 µg/m³ in 2023. Yet six of the world’s ten most polluted cities are in India. The capital, New Delhi, maintained consistently high pollution levels, with an annual average of 91.6 µg/m³, nearly unchanged from 92.7 µg/m³ in 2023,” the report added.