Mumbai recorded an air-quality score of 177 on IQAir's U.S. index on Oct. 20, placing the city in its unhealthy category and raising concerns about fine-particle exposure.
The score covered the hour ending 10 a.m. ET (14:00 UTC). IQAir listed fine particulate matter, known as PM2.5, at 93 micrograms per cubic meter and drew its city reading from six monitoring stations supplied by five contributors.
The World Health Organization (WHO) says fine-particle exposure is linked to illnesses affecting the lungs and heart. Children and people with existing health conditions are especially vulnerable, according to the agency.
The index used matters when comparing readings. IQAir's U.S. scale labels scores from 151 to 200 unhealthy, while India's Central Pollution Control Board (CPCB) calls scores from 101 to 200 moderate on its own scale. The Indian Express reported that Additional Municipal Commissioner Avinash Dhakane said a sudden pollution spike may show up sooner on a platform such as IQAir.
A December 2023 Maharashtra Pollution Control Board study identified vehicle emissions, dust stirred back into the air, biomass burning and industrial combustion as contributors to Mumbai's PM2.5 pollution. The study does not establish which sources drove the Oct. 20 reading.
The Brihanmumbai Municipal Corporation issued revised 28-point guidelines on Oct. 15, 2024, to address air pollution associated with construction and demolition.
