With haze continuing to shroud Mumbai’s skyline, the Brihanmumbai Municipal Corporation (BMC) has cited sea salt particles as one of the factors contributing to the haze, even as it acknowledged that particulate matter from vehicles and construction dust remains a major source of air pollution.Avinash Dhakane, additional municipal commissioner who heads the civic body’s environment department, said on Thursday that a source identification study by the Maharashtra Pollution Control Board (MPCB) had identified sodium chloride, the principal salt in seawater, as a contributor to the haze.“The NaCl reacts with pollutants emitted from vehicles and industries and leads to the production of haze in the atmosphere post chemical reaction,” Dhakane said at a press conference.However, the presence of sea salt does not by itself explain Mumbai’s deteriorating air quality. Sea spray can release salt aerosols into the atmosphere, while humidity can cause airborne particles to grow and scatter light, reducing visibility.Dhakane said PM2.5 and PM10 each accounted for 18 per cent of the city’s air pollution and continued to be among its primary pollutants. PM2.5 refers to fine particles that can penetrate deep into the lungs, while PM10 includes larger inhalable particles, including dust.Mumbai’s citywide air quality index (AQI) stood at 102 on Thursday, according to figures cited by the civic administration. Under the Central Pollution Control Board’s (CPCB) National Air Quality Index, a reading between 101 and 200 falls in the ‘Moderate’ category. This category indicates possible breathing discomfort among people with lung disease and asthma, children and older adults.According to the civic administration, Mumbai recorded air quality in the ‘Satisfactory’ category on 231 days till October 22 this year, compared with 185 days in 2023, 216 in 2024 and 222 in 2025. On Thursday, 10 of the 22 active monitoring stations reportedly recorded AQI levels in the ‘Moderate’ category.Story continues below this adWhile the administration cited the rise in days with ‘Satisfactory’ air quality as an improvement, these figures alone do not establish a sustained reduction in pollution. A meaningful assessment would also require comparable annual data on pollutant concentrations, monitoring coverage and the number of days falling into each AQI category.Also Read | As Mumbai chokes and swelters, 7,633 trees cleared for removal in five monthsThe BMC plans to use artificial intelligence (AI) to identify construction sites where pollution-monitoring sensors repeatedly stop functioning, a problem that civic officials say has prompted them to conduct physical inspections.The civic body has made the installation of sensors mandatory at construction sites and infrastructure projects to monitor dust pollution. Officials said sensors had been installed at around 3,000 sites across Mumbai.“We are planning to incorporate an AI system that will analyse a pattern about which are some of the sites that are frequently shutting their sensors down, what was their last reading recorded and how often does it happen. By this way, we will be able to identify developers who could be manipulating the sensors and take action against them,” Dhakane said.Story continues below this adAhead of Diwali, the civic administration has appealed to residents not to burst firecrackers in public spaces, citing concerns over air pollution.