, Oct. 18 -- Dhaka has ranked fourth on the list of cities worldwide with the worst air quality with an AQI score of 172 at 8:55 am this morning.

Dhaka's air was classified as 'unhealthy', according to the air quality index.

Pakistan's Lahore, India's Delhi and Uzbekistan's Tashkent occupied the first, second and third spots on the list, with AQI scores of 270, 236 and 182, respectively.

When the AQI value for particle pollution is between 50 and 100, air quality is considered 'moderate', between 101 and 150 is considered 'unhealthy for sensitive groups', between 151 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.

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