Lahore has once again been ranked as the world’s most polluted city with a particulate matter (PM) rating of 243, data from the Air Quality Index (AQI) showed Wednesday (today) morning. As per the latest data released by the Air Quality Index, Lahore leaving New Delhi behind in the list of most polluted cities around the world. Meanwhile, Karachi recorded a particulate matter (PM) rating of 173, placing the city at the fifth spot on the global index of the world’s most polluted cities. Moreover, at 175 AQI (Particulate Matter (PM) 2.5), Mongolian city Ulaanbaatar stood at the second position, Indian city Kolkata third and Delhi at the fourth position respectively in the list of most polluted cities in the world. According to the AQI air quality index, a pollution concentration score above 301 is considered hazardous to health. Lahore schools to close three days a week as smog worsens A day earlier, the Punjab government had decided to shut private and government schools in Lahore thrice a week as the smog situation in the provincial capital has risen at the hazardous level. In a notification, Punjab Relief Commissioner Babar Hayat Tarar had said the restriction would be in place from November 27 to January 15. Schools and offices will be closed on Saturday, Sunday, and Monday, the notification had said.