India, Jan. 24 -- The Air Quality Index (AQI) in the city rose to 104 - according to the Central Pollution Control Board (CPCB) - on Thursday, indicating the air was unhealthy for sensitive groups, after hovering at 80-90 for several days. A thick layer of smog engulfed large parts of the city till the afternoon, and doctors reported a surge in complaints about respiratory illness.

Data from CPCB showed multiple pollution hotspots across the city, while many air quality monitoring stations were non-functional for several hours, leading to gross underreporting of AQI levels.

Experts cautioned that air quality in the city was prone to sharp localised fluctuations.

A senior official from the Brihanmumbai Municipal Corporation (BMC) told H...