Dhaka of Bangladesh has once again topped the list of cities worldwide with the worst air quality, with an AQI of 174 at 9:20 am on Tuesday. The air was classified as 'unhealthy', according to the air quality and pollution(city) ranking.

An AQI between 151 and 200 is considered 'unhealthy' while 201-300 is 'very unhealthy', and 301+ is considered 'hazardous', posing severe health risks to residents.

Rising air pollution can cut life expectancy by more than five years per person in South Asia, one of the world's most polluted regions, according to a report published on Tuesday which flagged the growing burden of hazardous air on health.

The United Arab Emirates' Dubai and Indonesia's Jakarta occupied the second and third place in the list, with AQI scores of 166 and 160 respectively.

The region, which includes the world's most polluted countries Bangladesh, India, Nepal, and Pakistan, accounts for more than half of the total life years lost globally to pollution, the University of Chicago's Energy Policy Institute (EPIC) said in its latest Air Quality Life Index.

Rapid industrialization and population growth have contributed to declining air quality in South Asia, where impure pollution levels are currently more than 50% higher than at the start of the century and now major health hazards overshadow emerging threats.