Answer: Lahore
Notes: According to IQAir, Lahore’s air quality was the worst in the world, with the air quality index (AQI) at a “hazardous” 400. Lahore, the second-largest city in Pakistan, continues to suffer from a smog crisis that has affected the health and livelihood of millions of people. The AQI is calculated based on five categories of pollution: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Last month, Lahore was followed by Delhi at 302 and Karachi at 204.
