BANGKOK – The 2024 World Air Quality Report released by Swiss air technology firm IQAir reveals startling statistics about global air pollution, particularly spotlighting the dire situation across Asian cities. Alarmingly, nineteen out of the twenty cities with the highest levels of air pollution are located in Asia. The report notes tragic consequences for public health due to the high concentrations of fine particulate matter (PM2.5), which can penetrate deep within the lungs and bloodstream, causing serious health issues like respiratory and cardiovascular diseases.
According to the report published on March 11, 2025, Byrnihat, situated on the Assam-Meghalaya border, has now been recognized as the most polluted city globally, with its average PM2.5 level recorded at 128.2 micrograms per cubic meter (µg/m³). This statistic starkly contrasts with the World Health Organization's (WHO) recommended maximum annual average of 5 µg/m³—a troubling realization for air quality managers and the public alike.
The findings show India at the epicenter of the air pollution crisis, claiming thirteen of the top twenty cities on the list, including Mullanpur, Faridabad, and Loni, among others. The capital, Delhi, was reaffirmed as the world's most polluted capital city, with a PM2.5 average of 91.6 µg/m³. Despite these alarming figures, the nation has seen some improvement over the past year, recording a 7 percent reduction in PM2.5 pollution overall, with the national average dropping to 50.6 µg/m³.
"We have the data; now we need action," declared Soumya Swaminathan, former chief scientist at the World Health Organization. She highlighted the pressing need for government initiatives focusing on enhancing public transport, imposing higher fines on high-emission vehicles, and ensuring stricter regulations for industrial emissions. The continuous rise in air pollution threatens to lower India's life expectancy by approximately 5.2 years, as per IQAir’s report.
Chad has the dubious distinction of being the most polluted nation, where PM2.5 levels were measured at 91.8 µg/m³—over eighteen times higher than the WHO guidelines. Following closely are other nations like Congo and Bangladesh, underlining the global crisis faced by many developing countries where air quality is often compromised by industrialization and urbanization.
Interestingly, the report does reveal some regions making strides toward cleaner air. Australia and New Zealand stand out with 57 percent of cities meeting WHO air quality criteria, signaling effectiveness in their air quality management systems. Conversely, North America, particularly California, exhibits poor air quality levels, with Los Angeles ranking among the least air-friendly urban regions.
Within India, nearly 35 percent of the cities monitored exceeded the WHO guidelines for PM2.5 levels by over ten times, beckoning immediate action from the regional governments and regulators. The data serve as a clarion call for policymakers as much as it lays bare the health ramifications for the populace.
Public health experts warn of the long-term consequences of persistent air pollution, as 99 percent of the global population is exposed to unsafe air concentrations above WHO recommendations. Such exposure can lead to chronic health problems, necessitating enhanced public awareness and introspection from governmental authorities about the sustainability of current practices.
Among metropolitan cities, the air quality picture varied. While Delhi recorded 108.3 for its air quality index (AQI), Mumbai's air quality saw improvements with the PM2.5 level dropping from 43.8 µg/m³ to 33.7 µg/m³ this year. Kolkata too exhibited some recovery, inching down slightly from 47.8 to 45.6 µg/m³, reflecting the uneven nature of air quality improvements across different regions.
Hyderabad, Bengaluru, and Chennai have also demonstrated declines, with their PM2.5 levels recording 30.6, 30.0, and 26.0 µg/m³ respectively. Yet, with regional authorities reiteratively facing challenges during the annual smog season, it is imperative for all stakeholders to work collaboratively toward establishing practical solutions to the air pollution crisis.
Looking forward, the 2024 World Air Quality Report serves as the latest reminder of the foothold air pollution has on public health and the urgent need for structured and sustained interventions, both locally and internationally. The data presented is more than just numbers; it embodies the struggle for cleaner air and the longer-term ramifications for health and quality of life for millions.
Across Asia, cities not only need to adapt immediate measures to improve air quality, but it also calls for larger international cooperation to undertake this shared responsibility. With air pollution being labeled as one of the leading causes of premature death globally, it emphasizes the necessity for deliberate actions today for tomorrow's wellbeing.