At the same time, Malaysia's Kuching topped the list of the world's most polluted cities with a score of 346. Kinshasa of Congo was in second place with a score of 168. India's Kolkata was third with 164, and Malaysia's Kuala Lumpur was fourth with 160.

According to IQAir's index, air quality is 'good' between 0 and 50, 'moderate' between 51 and 100, and 'unhealthy for sensitive groups' between 101 and 150. Scores from 151 to 200 are considered 'unhealthy', 201 to 300 'very unhealthy', and above 301 'hazardous'.

Air pollution is especially risky for children, the elderly, sick people, and pregnant women. In Bangladesh, PM10, PM2.5, nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and ozone (O3) are considered in determining air quality.

A 2019 report by the Department of Environment and the World Bank identified brick kilns, vehicular smoke, and construction dust as the main sources of air pollution in Dhaka.

According to the World Health Organization (WHO), air pollution increases the risk of stroke, heart disease, chronic obstructive pulmonary disease (COPD), lung cancer, and acute respiratory infections. Approximately 7 million people die every year worldwide due to air pollution.