Dhaka woke up to another morning of hazardous air on Thursday, with winter fog trapping pollutants over the city and pushing air quality deeper into the ‘unhealthy’ category.At 9:15 am, the overcrowded capital of Bangladesh ranked eighth among cities with the worst air quality in the world, recording an Air Quality Index (AQI) score of 163. According to the AQI scale, such a reading signifies ‘unhealthy’ air, increasing health risks for the city’s millions of residents.Globally, Afghanistan’s Kabul topped the list with an AQI score of 429, indicating extremely dangerous air conditions. Indian cities Kolkata and Delhi followed in second and third positions with scores of 244 and 235, while Egypt’s Cairo ranked fourth with a reading of 179.The AQI is used worldwide to communicate daily air quality levels and their potential health impacts. An AQI score between 50 and 100 is considered ‘moderate’, while readings from 101 to 150 are labelled ...