Dhaka's air quality was "unhealthy" yesterday morning.

With an air quality index (AQI) score of 161 at 8:57am, Dhaka ranked 5th in the list of cities worldwide with the worst air quality.

Chile's Santiago, Vietnam's Hanoi and Thailand's Chiang Mai, occupied the first three spots in the list, with AQI scores of 180, 170 and 169, respectively.

An AQI between 101 and 150 is considered "unhealthy", AQI between 201 and 300 is said to be "very unhealthy", while a reading of 301+ is considered "hazardous", posing serious health risks to residents.

Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon.

As per the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, largely as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.