The air quality in Lahore remained hazardous for the fourth consecutive day as Punjab's capital city on Sunday was at the top number in the list of the world's most polluted cities.

Lahore's air quality index (AQI) was 317 on Sunday (today). In the last three days the air quality index in the city was 317 on Nov 20, 347 on Nov 19 and 343 on Nov 18 respectively, according to IQAir, a Swiss air quality technology company that operates real-time air quality operation.

As per the worldwide major air quality index on Sunday, India's capital Delhi was on the second number with 206 AQI and Kolkata third with 186 AQI. The air quality in both cities of the neighbouring country was very unhealthy and unhealthy respectively.

Sahiwal was most polluted city in Pakistan on Sunday having 438 AQI, while Bahawalpur was on the second number with 382 AQI.

In an effort to tackle smog, the Lahore High Court (LHC) on Thursday directed the Punjab government to issue a notification to private offices in Lahore to halve staff attendance.

Air pollution has worsened in Pakistan in recent years, as a mixture of low-grade diesel fumes, smoke from seasonal crop burn off, and colder winter temperatures coalesce into stagnant clouds of smog.