March 12, 2025
DHAKA – Bangladesh was the world’s second most polluted country in 2024, with average smog levels exceeding World Health Organization (WHO) guidelines by more than 15 times, according to data compiled by Swiss air quality monitoring firm IQAir.
With an average PM2.5 level of 78 micrograms per cubic meter (µg/m³), Bangladesh had the worst air quality in the world, second only to Chad (128 µg/m³). It was followed by Pakistan (73.7 µg/m³), the Democratic Republic of the Congo (58.2 µg/m³), and India (50.6 µg/m³) in fifth place.
The data also revealed Dhaka was the world’s third most polluted capital in 2024, with an average PM2.5 level of 78 µg/m³. The Indian capital, New Delhi, was the most polluted (91.6 µg/m³), closely followed by N’Djamena, the capital of Chad (91.8 µg/m³). Kinshasa, the capital of the Democratic Republic of the Congo (58.2 µg/m³), ranked fourth, while Pakistan’s capital, Islamabad (52.4 µg/m³), came in fifth.
According to data released on Tuesday by IQAir, only seven countries met WHO air quality standards in 2024. Researchers warned that tackling smog would become even more challenging following the United States’ decision to shut down its global air quality monitoring efforts. IQAir reported that only Australia, New Zealand, the Bahamas, Barbados, Grenada, Estonia, and Iceland met the WHO’s air quality standards last year.
India saw a 7% decline in its average PM2.5 levels, bringing it down to 50.6 µg/m³. However, the country still had 12 of the world’s 20 most polluted cities. Byrnihat, an industrial town on the border of Meghalaya and Assam, was the most polluted city, with an average PM2.5 level of 128 µg/m³.
The study analysed data from over 40,000 air quality monitoring stations across 8,954 locations in 138 countries, territories, and regions. The WHO recommends PM2.5 levels of no more than 5 µg/m³—a standard met by only 17% of cities worldwide in 2024.
Significant data gaps, particularly in Asia and Africa, obscure the global picture. Many developing nations have depended on air quality sensors installed at U.S. embassies and consulates to monitor pollution levels. However, the U.S. State Department recently ended this program due to budget constraints, removing over 17 years of data from the government’s official air quality monitoring website, AirNow.gov.
“Air pollution remains a critical threat to both human health and environmental stability, yet vast populations remain unaware of their exposure levels,” said Frank Hammes, Global CEO of IQAir. He emphasised that the U.S. has recognised access to clean air as a universal human right.
According to WHO, 99% of the global population lives in areas that fail to meet recommended air quality levels. Air pollution is the second leading global risk factor for death and the second leading cause of mortality among children under five, following malnutrition. In 2021 alone, air pollution was responsible for 8.1 million deaths, with 58% of these attributed to ambient PM2.5 pollution.
Exposure to PM2.5 is linked to numerous health conditions, including asthma, cancer, strokes, and lung diseases. Additionally, exposure to high levels of fine particulate matter during pregnancy and early childhood has been associated with congenital heart defects, eczema, allergic diseases, cognitive impairments, neurodevelopmental disorders, and mental health issues.