** On Monday, Lahore was ranked the second most polluted city in the world.**

According to IQAir an air quality index (AQI) between 0 and 50 is considered good. Whereas, anything over 300 is considered hazardous and requires emergency response and caution from people.

On Monday morning, Lahore had an AQI of 351, which is categorized as hazardous. During the afternoon, Lahore's AQI dropped to 212, taking it to third place in the ranking.

IQAir's database shows that the ranking of cities fluctuates according to the AQI number's rise or decline. The data can be monitored live and changes regularly.

When the AQI exceeds 300, health experts advise people to avoid outdoor activities as they may experience more serious health effects. Meanwhile, Delhi was ranked at the top with an AQI of 544.

According to the World Health Organization's (WHO) 16 of the 20 most polluted cities in the world are in northern India and Pakistan. Lahore, Bahawalpur, Faislabad, Karachi, Multan, and other cities are ranked prominently among the most polluted cities globally.

Agricultural practices like crop burning, traffic pollution, industry and rubbish burning have contributed to the air pollution problems in both India and Pakistan.