Dhaka, the overcrowded capital city of Bangladesh, topped the list of cities with the worst air quality with an AQI score of 171 at 9:05am on Wednesday.
Its air was classified as unhealthy, referring to a health threat to residents, according to the AQI.
When the AQI value for particle pollution is between 50 and 100, air quality is considered moderate, between 101 and 150, air quality is considered unhealthy for sensitive groups, between 150 and 200 is unhealthy, between 201 and 300 is said to be very unhealthy, while a reading of 301+ is considered hazardous' posing serious health risks to residents.
China’s Beijing, Uganda’s Kampala and Thailand’s Chiang Mai cities occupied the second, third and fourth spots on the list, with AQI scores of 167, 161 and 160 respectively.
The AQI, an index for reporting daily air quality, informs people how clean or polluted the air of a certain city is and what associated health effects might be a concern for them.
The AQI in Bangladesh is based on five pollutants: particulate matter (PM10 and PM2.5), NO2, CO, SO2 and ozone.
Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon.
Per the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, mainly due to increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.
