While Mumbai gasps now, experts see hope for cleaner air this winter

As winter approaches Mumbai could once again find itself gasping for air For two consecutive years the city has choked on rising pollution levels through the cold months mdash and while experts predict a slight improvement this season it wonrsquot be because the city has curbed its emissionsMeteorologist Dr Gufran Beig founderdirector of the System of Air Quality and Weather Forecasting and Research SAFAR says that any relief Mumbai experiences this year will come from La Nina a natural weather cycle that brings cleaner ocean air toward the coast mdash not from better pollution controlWhat is Mumbairsquos situationAbout 40 per cent of the worst AQI Air Quality Index days recorded in Mumbai in 2023 and 2024 were during the winter months of December January and February according to data from the Central Pollution Control Board CPCB analysed by middayIn 2023 Mumbai recorded 145 days in the lsquomoderatersquo AQI category and 35 days in the lsquopoorrsquo category totalling 180 days of bad air Of these 45 days were in winter mdash 4055 per cent of the total Similarly in 2024 the city again saw 145 lsquomoderatersquo days and 2 lsquopoorrsquo days with 70 of those days falling in winter mdash 3945 per cent of the totalOver the past two weeks Mumbairsquos AQI has remained in the lsquomoderatersquo range 160ndash165 as per CPCB data The main pollutants have been PM25 PM10 and ozone On Sunday the cityrsquos overall AQI stood at 160 with PM25 as the dominant pollutantWinter worsens pollutionExperts say winter air is heavier and drier preventing dust and other pollutants from dispersing During the monsoon moisture and rainfall help settle these particles In contrast the cooler stagnant winter air traps pollutants closer to the surface Mumbairsquos pollution problem is primarily driven by construction dust and vehicular emissions both of which have surged in the postpandemic yearsWill this year be differentAccording to experts Mumbai is likely to see better air quality this year if weather patterns alone are considered Gufran Beig meteorologist and founderdirector of the System of Air Quality and Weather Forecasting and Research SAFAR said ldquoThis year compared to last year the situation may improve but it has nothing to do with a decrease in combustion or pollution in the airrdquo Beig linked this forecast to a climatological phenomenon associated with La NinaHe explained ldquoLa Nina has always been associated with good air quality in Mumbai It is a cyclical phenomenon that appears every three years During this period wind patterns shift in a way that increases the frequency of clean air moving from the ocean toward land In recent months we have seen a neutral condition between El Nino and La Nina known as an ENSO condition As a result emissions from the city are often neutralised by sea winds Yet Mumbai fares comparatively worse than Chennai another coastal city mdash entirely due to higher local emissionsrdquoManoj Kumar analyst at the Centre for Research on Energy and Clean Air CREA said ldquoMumbai typically experiences a rise in air pollution during the winter months As temperatures drop shallow temperature inversions form mdash especially during early mornings and late evenings mdash which reduce vertical air mixing At the same time the weakening of the cityrsquos seabreeze and landbreeze circulation slows pollutant dispersion This allows emissions from traffic construction industries and power plants to accumulaterdquoHe added ldquoHotspots such as Deonar and BandraKurla Complex are already significantly polluted and may experience air quality levels in the very poor to severe categories during this period These areas regularly record some of the highest pollutant concentrations in the city highlighting the need for effective hotspotbased pollution control measures For the 2025 winter period Mumbairsquos air quality is expected to remain mostly in the moderate to poor range with occasional very poor episodes during lowwind and inversion conditions While ongoing pollution control efforts may help to some extent local emissions and seasonal drops in natural ventilation are likely to continue driving persistent pollution challenges through the winterrdquo