Lahore again ranked second most polluted city in world today as Air Quality Index hits 328

• An AQI ranking between 301-500 or above is classified as hazardous.
• Delhi holds the top spot on the list with an AQI of 556, followed by Lahore in second place.

Lahore's air quality remained hazardous on Wednesday with an air quality ranking of 328, according to Air Visual's Air Quality Index (AQI) list.

Lahore is ranked the second most polluted city in the world, in the AQI list, while India's capital Delhi holds the top spot with an AQI of 556. According to Air Now, an AQI ranking between 301-500 or above is classified as hazardous. "AQI greater than 300 would trigger health warnings of emergency conditions. The entire population is more likely to be affected," Air Now said.

Meanwhile, Karachi is ranked at seventh on the list published Wednesday morning. Karachi has an AQI of 156 and is classified as unhealthy.