Air quality worsens in Mumbai, Thane, and Navi Mumbai in first four days of 2026 | Mumbai News

Mumbai: Air quality across the Mumbai Metropolitan Region has deteriorated sharply since the start of the new year, with average Air Quality Index (AQI) slipping from the ‘satisfactory’ to ‘moderate’ — and in some pockets, even ‘poor’ — category over the last four days. Mumbai recorded an average AQI of 140 on Sunday, up from 106 on Saturday and significantly higher than 79 on Friday and 90 on Thursday. Thane city also saw a steady worsening, with its average AQI rising to 124 from 82 on Jan 1, while Navi Mumbai, which had recorded AQIs of 99 and 86 on Jan 1 and 2, respectively, deteriorated sharply to an average of 151 by Sunday. Environmental experts attributed the worsening air quality to a combination of unfavourable winter conditions and persistent dust pollution.Several localities reported pollution levels well above the city averages. In Mumbai, Byculla recorded the highest AQI at 184, followed by the area around the Chhatrapati Shivaji Maharaj International Airport at 167, placing both at the higher end of the ‘moderate’ category. In Navi Mumbai, air quality slipped into the ‘poor’ category in some areas, with Nerul recording an AQI of 206 and Sanpada emerging as the most polluted locality at 215.AQI is a concentration of toxic particulate matter PM2.5 or PM10 in the air, whichever is higher. As per the Central Pollution Control Board’s classification, AQI readings of up to 50 is considered good, 51–100 satisfactory, 101–200 moderate, 201–300 poor, 301–400 very poor, and above 400 severe.Prolonged exposure to ‘moderate’ category air can cause minor respiratory discomfort, particularly among sensitive groups such as children, the elderly, and those with pre-existing lung or heart conditions. Breathing ‘poor’ air — such as the levels recorded in Nerul and Sanpada on Sunday — can cause breathing discomfort to most people, especially with prolonged exposure.Bhagwan Kesbhat, CEO of environmental organisation Waatavaran, said falling temperatures within the winter months cause pollutants to get trapped closer to the ground. “Without clear skies and adequate wind movement, dispersion becomes difficult and pollution levels rise sharply,” he said. Kesbhat added that the Maharashtra Pollution Control Board (MPCB) and Brihanmumbai Municipal Corporation (BMC) have claimed to have taken steps to curb dust emissions from construction sites — which contribute nearly 30% of the city’s pollution load — but data over several years shows that the share of construction dust in Mumbai’s overall air pollution has largely remained unchanged.