While the Bombay High Court (HC) criticized the local government bodies of Mumbai and Navi Mumbai for failing to control air pollution in Mumbai, data from the Central Pollution Control Board (CPCB) shows that Mumbai has recorded the maximum number of days with unhealthy air quality index (AQI) in 2026, so far, compared to the neighboring regions of Navi Mumbai, Thane and Vasai-Virar in the Mumbai Metropolitan Region (MMR).
The CPCB panel shows that AQI readings between 0 and 50 are considered good or safe, 51 to 100 are considered satisfactory, 101 to 200 are considered moderate, 201 to 300 are considered poor, 301 to 400 are considered very poor and above 400 are considered severe.
According to CPCB data, Mumbai has recorded 18 days of unhealthy AQI this year between January 1 and January 24.
The CPCB dashboard shows that during this period AQI readings remained between 120 and 150, which is in the moderate category and classified as unhealthy for sensitive groups, especially children and elderly people.
Further, the data also shows that during the 24-day period, Mumbai recorded only six days of satisfactory AQI.
In comparison, Navi Mumbai recorded 15 days of unhealthy AQI and nine days of satisfactory AQI, followed by Vasai Virar, which recorded 13 days of unhealthy AQI and 10 days of satisfactory AQI, and Thane, which was followed by 12 days of unhealthy AQI and 12 days of satisfactory AQI. Mira Bhayander has recorded 13 days of unhealthy AQI and nine days of satisfactory AQI.
Inadequate emissions levels and monitoring system at MMR
Meanwhile, officials of the Brihanmumbai Municipal Corporation (BMC) and the Maharashtra Pollution Control Board (MPCB) have attributed the pollution load to man-made factors such as vehicle emissions, shifting dust and construction work.
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“Mumbai has the highest vehicle density compared to other regions in the MMR and vehicle emissions have been identified as the main cause of pollution in the city. Apart from this, Mumbai is also witnessing a major spate of construction work for various public and private projects. This particular factor has also contributed to the deterioration of AQI levels in the city,” an official said.
At present, Mumbai has 28 ICA monitoring stations. In comparison, Thane has two stations at Kasarvadavali and Upvan Fort, Navi Mumbai has six stations at Nerul, Mahape, Sanpada, Vashi, Kalamboli and Taloja. While Virar and Mira Bhayander have only one station each under their jurisdiction.
“Mumbai is also intensely monitored compared to the rest of the regions in MMR. This is also a reason why the numbers are bad in Mumbai. In comparison, other areas like Thane or Bhayander do not show a drop in AQI levels on most days, probably because they are not intensively monitored as the number of AQI monitoring stations there are are not adequate,” said an MPCB official.
Meanwhile, officials said that the ICA monitoring station is being expanded and three additional stations will be set up in each district of Thane, Vasai Virar and Kalyan-Dombivali.
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Two stations will be set up in Mira-Bhayander, Ulhasnagar and Bhiwandi Nizampur areas. Officials said each of these stations will cost Rs 9 crore.
“The work order has been issued to procure these stations and they will be supplied to us in a phased manner from next month. Before winter, when the city’s AQI usually worsens, we will have more stations installed to monitor and identify areas registering poor AQI and we will be able to mitigate them accordingly,” an official told The Indian Express.
“The plan to increase the number of tracking stations is part of a larger project in which we aim to set up more than 50 tracking stations across the state of Maharashtra,” the official added.
Climate ‘disadvantage’
For a city like Mumbai, which is very close to the Arabian Sea, consistently recording a poor AQI is rare as coastal cities experienced faster wind reversals, a phenomenon that removes dust particles that remain accumulated in the lower atmosphere.
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However, atmospheric experts argued that the geographical advantage of being close to the country’s western coast has now become a disadvantage due to global climate change phenomena.
“Due to global climate change, the air inversion process has become very slow and Mumbai’s proximity to the western coast also makes it vulnerable to dust particles being blown towards the continent from the Thar Desert and also humid air coming towards the eastern edge of the globe from the Middle East,” Dr Gufran Beig, atmospheric scientist and senior professor at the National Institute for Advanced Studies (NIAS) – Indian Institute of Sciences (IISC), told the Indian Express.
“Land and sea breeze can only disperse pollutants to a limited extent. We have to understand that apart from being surrounded by sea, Mumbai is also surrounded by other satellite districts like Thane, Kalyan Dombivali, which contributed largely to the emissions due to economic activities taking place there. Apart from these, factors like vehicle emissions and regional transport movement also play a role,” Dr Sachida Nand Tripathi, atmospheric scientist and dean, School of Sustainability Kotak – IIT Kanpur and member of the National Said Clean Air Program (NCAP) steering committee.