In May 2024, Kathmandu was declared as the world’s most polluted city, according to real-time data from the Air Quality Index (AQI). Ranking 162 on the index, Kathmandu surpassed Chiang Mai in Thailand and Medan in Indonesia, raising alarms about the growing air quality crisis in South Asia.
Similarly, the World Bank released a report in June 2025 stating that air pollution is a major factor for death and disability in Nepal. “Single-sector solutions are not sufficient to meet any clean air target. Public policy and investment need to optimize air quality actions across sectors, prioritizing those with the most cost-effective solutions,” the report states.
Air pollution reduces life expectancy by 3.4 years for the average Nepali and causes approximately 26,000 premature deaths annually. In addition to health, air pollution impacts labor productivity, tourism, and the aviation sector. The economic cost of poor air quality is equivalent to more than 6 percent of Nepal’s Gross Domestic Product (GDP) each year.
Experts attribute the surge in pollution levels to a combination of increasing temperatures and widespread forest fires that have led the Kathmandu Valley to the state. This alarming spike underscores a broader regional crisis: air pollution in South Asia is cutting lives short at an unprecedented rate.
The data from the Air Quality Life Index (AQLI), developed by the University of Chicago’s Energy Policy Institute reveals that air pollution remains the single greatest external threat to life expectancy in South Asia. The report shows that the average life expectancy in the region is reduced by three years due to air pollution. In the most polluted areas, that figure exceeds eight years. Across India, Bangladesh, Nepal, and Pakistan, the health burden from particulate pollution is nearly twice that of childhood and maternal malnutrition, and more than five times greater than that of unsafe water and sanitation.
This data makes clear that particulate pollution is the world’s greatest external risk to human health. Its impact on life expectancy is comparable to that of smoking, more than four times that of high alcohol use, five times that of transport injuries like car crashes, and more than six times that of HIV/AIDS.
Nearly 2bn people in South Asia are breathing air that far exceeds the World Health Organization (WHO) guideline for PM₂.₅—fine particulate matter known to damage lungs and the cardiovascular system. Most countries in the region are also failing to meet their own, far more lenient, national air quality standards.
In Nepal, PM₂.₅ concentrations reached 38.3 µg/m³ in 2023—a 10 percent increase over the previous year. According to the AQLI report, “The average Nepali could gain three and half years of life if the country met WHO air quality standards. In heavily polluted districts such as Mahottari and Rautahat, residents could gain more than five and half years of life expectancy,” the report states.
In response, the government has implemented an Air Quality Management Action Plan 2020 for the Kathmandu Valley. The strategy focuses on strengthening emissions monitoring and data collection, regulating polluting sectors like transport, brick kilns, and construction and promoting sustainable urban planning and eco-friendly infrastructure. Experts warn that without aggressive action, the health crisis will worsen.
Globally, pollution increased slightly in 2023, with wildfire-driven particulate matter emerging as a new challenge, even in developed countries. In Canada, PM₂.₅ levels doubled, marking the highest pollution in 26 years. Wildfire smoke affected vast swaths of the US, pushing several Midwest and Southern counties into the ranks of the nation’s most polluted—surpassing California for the first time in five years.
“We are now stuck living with air pollution concentrations that are the dangerous ghost of the fossil fuels burned since the Industrial Revolution,” says Michael Greenstone, AQLI co-creator and Milton Friedman Distinguished Service Professor at the University of Chicago. “Even countries that have earnestly spent decades cleaning up their air can’t escape these ghosts and the shorter and sicker lives they deliver.”
A significant barrier to tackling pollution is the lack of real-time air quality data. According to AQLI again, nearly 70 percent of the world’s population lives in countries with fewer than three air quality monitors per million people and that leaves 5bn people—many in the most polluted regions without access to basic information about the air they breathe
“Access to information is critical,” says Christa Hasenkopf, director of the Clean Air Program at EPIC. “While data can catalyze action, it must be backed by political will, ambitious policy, and consistent enforcement.”
If global air quality were brought in line with WHO guidelines, the average person could gain 1.9 additional years of life, saving a combined 15.1bn life-years worldwide. Yet, for South Asia, the need is especially urgent. Pollution in the region rose 2.8 percent from 2022 to 2023, following a brief dip the year prior. Despite temporary improvements, the trend remains dire—reinforcing that particulate pollution is not just a public health concern, but a full-blown humanitarian crisis.
Each year, the AQLI takes on a different topic related to air pollution. This year, the report focused on access to air quality information—a topic EPIC has been deeply involved with over the last decade, including through the AQLI. When people understand that the air they breathe is harmful to their health, they can take steps to reduce the hazard by purchasing air purifiers, wearing masks, limiting time outdoors, and using the data to inform policy actions.
“The analysis shows that improving life expectancy in South Asia will require policies that bring air quality in line with current standards and, over time, move toward stricter limits. Evidence from other regions demonstrates that targeted, sustained action can rapidly reduce PM₂.₅ and deliver measurable gains in longevity”, says AQLI Director Tanushree Ganguly. “Throughout history, countries have grown and developed while improving air quality. Targeting fossil fuels at their source will help clean local air and combat climate change. But countries need better data and stronger policies to make that happen.”
