El Niño is a climate phenomenon associated with the abnormal warming of surface waters in the central and eastern equatorial Pacific Ocean. Its effects on weather patterns vary across regions. (Credit: Express Photo by Sankhadeep Banerjee)Mumbai has ranked as the fifth most polluted city in the world and the most polluted in India, according to global air quality assessment platform iQAir, as the city continues to experience unusually hot and humid weather following a rain-deficient monsoon.The city recorded an Air Quality Index (AQI) of 152 on Thursday, categorised as unhealthy, with ground-level ozone (O3) identified as the primary pollutant, according to iQAir, a US-based air quality monitoring organisation.The reading comes amid a spell of above-normal temperatures following the early withdrawal of the monsoon. Mumbai has recorded its hottest days in at least a decade on three occasions this month, with maximum temperatures hovering 4-5 degrees Celsius above normal on several days.“This year, Mumbai is experiencing an El-Niño pattern of climate, as a result of which the wind speed has slowed down tremendously while the overall temperature is hot and humid. This factor is preventing air circulation as a result the pollutants are getting settled in the lower atmosphere leading to rise in pollution levels,” atmospheric scientist Gufran Beig, chair professor at the National Institute of Advanced Studies (NIAS), Indian Institute of Science (IISc) told The Indian Express.El Niño is a climate phenomenon associated with the abnormal warming of surface waters in the central and eastern equatorial Pacific Ocean. Its effects on weather patterns vary across regions.Ground-level ozone, unlike the protective ozone layer in the upper atmosphere, is a pollutant formed when nitrogen oxides and volatile organic compounds react in the presence of sunlight. Its concentrations can rise during hot, sunny conditions.The iQAir list covered 122 cities worldwide. Mumbai was followed by Delhi, ranked sixth with an AQI of 151, while Kolkata was placed tenth with a reading of 124.‘Satisfactory’ air qualityStory continues below this adThe readings on the Central Pollution Control Board’s (CPCB) dashboard, however, presented a different picture of Mumbai’s air quality, with the city’s AQI at 98, categorised as satisfactory.Of the 23 air quality monitoring stations operational in Mumbai, 12 recorded satisfactory air quality.Deonar had an AQI of 156, followed by Bandra Kurla Complex (145), and Khindipada in Bhandup (129). The CPCB identified PM2.5 and PM10 as the major pollutants at these locations.“If garbage or plastic waste are being burnt at Deonar, the air over there doesn’t stay confined to that place. That is why one can see that places like Chembur and Kurla which are close to Deonar are also seeing unhealthy AQI as air keeps travelling and spreading pollution levels,” an official of the Maharashtra Pollution Control Board (MPCB) told The Indian Express.Story continues below this adThe Brihanmumbai Municipal Corporation (BMC) has directed officials in all 26 wards to identify pollution hotspots and implement local measures to address them.Pratip Acharya is a seasoned journalist based in Mumbai reporting for The Indian Express. With a career spanning over a decade, his work demonstrates strong Expertise and Authority in critical urban issues, civic affairs, and electoral politics across Eastern and Western India. Expertise & Authority Current Role: Journalist, The Indian Express (IE), reporting from Mumbai. Core Authority: Pratip's reporting focuses sharply on local democracy and development, specializing in: Urban Governance and Civic Affairs: Providing in-depth analysis of municipal decision-making, city planning, and local infrastructure, essential for informed urban reporting. City Politics and Environment: Covering the political dynamics of Mumbai and surrounding areas, alongside critical environmental challenges impacting the metro region. Electoral Coverage (High-Stakes Experience): He has extensive experience in high-stakes political reporting, having covered major elections, establishing his Trustworthiness in political analysis: National: Lok Sabha elections in 2014 and 2019. State: West Bengal Assembly elections in 2016 and Maharashtra Assembly elections in 2019. Major Assignments (Ground Reporting): Pratip demonstrated commitment during crises by conducting ground reporting throughout the Covid-19 pandemic since its breakout in 2020, offering first-hand accounts and analysis of the public health crisis. Experience Extensive Experience: Starting his career in 2014, Pratip has built his foundation across multiple prominent English dailies: Started at The Times of India in Kolkata (2014). Relocated to Mumbai (2016) and worked with The Free Press Journal and Hindustan Times before joining The Indian Express. Pratip Acharya's diverse experience across major publications, coupled with his specialized focus on the intricate details of urban governance and a track record of covering major electoral and health crises, establishes him as a trusted and authoritative source for news from India's critical metropolitan centres. ... Read MoreStay updated with the latest - Click here to follow us on InstagramTags:Mumbai