Thirteen of the world’s 20 most polluted cities are in India, with Byrnihat in Meghalaya topping the list, according to the World Air Quality Report 2024 by Swiss air quality technology company IQAir.
Overall, 35 percent of Indian cities reported annual PM2.5 averages exceeding 10 times the WHO guideline, it said. Delhi remains the most polluted capital city globally while India ranked as the world’s fifth most polluted country in 2024, down from third in 2023, according to the report.
Only 17 percent of global cities meet WHO air pollution guidelines.
Chad was the most polluted country last year, followed by Bangladesh, Pakistan, Democratic Republic of Congo, and India.
What the data says about Indian states
IQAir said that India saw a 7 percent 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 nine most polluted cities are in India.
Most of the Indian cities in the list are concentrated in Northwest India from Rajasthan to Western UP. They include Bhiwadi, Ganganagar and Hanumangarh in Rajasthan; Mullanpur in Punjab; Faridabad and Gurugram in Haryana; Loni, Muzaffarnagar, Noida and Greater Noida in Uttar Pradesh.
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. Severe pollution episodes persisted in 2024, particularly in northern states. January air quality was especially poor in Delhi and Himachal Pradesh. The city of Baddi, in southwestern Himachal Pradesh, saw a January monthly PM2.5 average of 165 μg/m3.
Air quality deteriorated sharply in Manipur in October, while November saw extreme pollution levels in Delhi, Punjab, Chandigarh, Haryana, and Himachal Pradesh with crop stubble burning remaining a major contributor to PM2.5 levels, accounting for 60 percent of pollution during peak periods.
Data, monitoring gaps
Countries, territories, and regions in Africa and Central and South Asia continue to report the highest population-weighted annual average PM2.5 concentrations, according to the report. While Africa’s air quality monitoring network is expanding, data availability remains inconsistent, with only 24 out of 54 countries or territories reporting data in 2024. West Asia is also underrepresented and requires more robust monitoring. Although Iraq was added to the report this year, key omissions remain, including Afghanistan, Iran, and Oman, it said.
Overall, 10 new countries or territories were included in the 2024 report compared to 2023, with the majority coming from Africa and the Latin America and Caribbean region. Globally, only 12 countries or territories recorded PM2.5 concentrations below the WHO guideline of 5.0 μg/m3, most of which were in the Latin America and Caribbean or Oceania regions.
In 2024, non-government-operated air quality monitoring provided the only real-time data for several countries and territories, including Afghanistan, Albania, Antarctica, Armenia, the Bahamas, Barbados, Benin, Bermuda, Bolivia, Burundi, Cambodia, Cameroon, Cape Verde, Costa Rica, Djibouti, the Dominican Republic, Eswatini, French Polynesia, Gabon, the Gambia, Greenland, Grenada, Guyana, Honduras, Jamaica, Lebanon, Libya, the Maldives, Mauritius, Montserrat, Morocco, Nicaragua, Panama, San Marino, Sudan, Suriname, Svalbard and Jan Mayen, Tanzania, Tonga, Trinidad and Tobago, the U.S. Virgin Islands, Uruguay, Venezuela, Zambia, and Zimbabwe.
Only 12 countries, regions, and territories recorded PM2.5 concentrations below the WHO annual PM2.5 guideline of 5.0 μg/m3, most of which were in the Latin America and Caribbean or Oceania region. In 2024, 17 percent of cities included in the report met the WHO annual PM2.5 guideline level, up from 9 percent in 2023. While this marks some progress, much more work has yet to be done to protect human health, especially that of children.
Reduced life expectancy
The data used to create the IQAir report was compiled from over 40,000 air quality monitoring stations and low-cost sensors worldwide, operated by research institutions, government agencies, schools, universities, non-profit organisations, private companies, and citizen scientists.
Particulate matter pollution, particularly PM2.5, poses significant health risks to children due to their unique physiological and behavioural characteristics. Children are more vulnerable to air pollution because they breathe more air per unit of body weight than adults. Combined with their higher relative respiratory rate, this results in children receiving larger doses of air pollution than adults when exposed to the same environment. Additionally, children have less effective nasal filtration and are more likely to breathe through their mouths, bypassing some of the body’s natural defenses against airborne particles. These factors collectively heighten their risk of respiratory and other health issues from air pollution.
Air pollution remains a significant health burden in India, reducing life expectancy by an estimated 5.2 years, it said. According to a Lancet Planetary Health study last year, about 1.5 million deaths in India every year from 2009 to 2019 were potentially linked to long-term exposure to PM2.5 pollution.
PM2.5 refers to tiny air pollution particles smaller than 2.5 microns, which can enter the lungs and bloodstream, leading to breathing problems, heart disease and even cancer. Sources include vehicle exhaust, industrial emissions and the burning of wood or crop waste.
In October 2024, India’s Supreme Court affirmed that breathing clean, pollution-free air is a fundamental right. The court found that the centre and the governments of Delhi, Punjab, Haryana, Uttar Pradesh, and Rajasthan must more effectively control air pollution at its source. Despite numerous rulings requiring government action, the court determined that the governments had taken only limited action to curb stubble burning and must submit reports demonstrating compliance with court orders. During a November hearing, the Supreme Court criticised Delhi officials for “serious lapses” in curbing pollution under the Graded Response Action Plan, multi-stage emergency measures for reducing pollution during poor air quality days
Air pollution is a crisis, for every single one of us, young and old. That’s why we have launched the Fight To Breathe – a collaborative campaign to tackle air pollution. Here’s how you can join the fight. And click here to power the campaign.
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