Dhaka: With Air Quality Index (AQI) rising to a score of 251 on Thursday, Dhaka topped the list of most polluted cities in the world.
An AQI between 201 and 300 is said to be 'very unhealthy', while a reading of 301 to 400 is considered 'hazardous', posing serious health risks to residents.
India's Kolkata and Vietnam's Hanoi occupied the second and third spots on the list, with an AQI score of 201 and 192, respectively.
In Bangladesh, the AQI is based on five criteria pollutants, namely particulate matter (PM10 and PM2.5), NO2, CO, SO2 and ozone.
The city's quality usually turns unhealthy in winter and improves during the monsoon.
Air pollution consistently ranks among the top risk factors for death and disability worldwide.
As per the World Health Organization, air pollution kills an estimated 7 million people globally every year, largely as a result of increased mortality from strokes, heart diseases, chronic obstructive pulmonary diseases, lung cancers and acute respiratory infections.
Dhaka, one among the most densely populated cities in the world, has long been grappling with air pollution issues.
Source: IANS