Mumbai heading underwater? UN flags city at risk of permanent inundation
Mumbai, Kolkata and Dhaka face threat of mass displacement as global sea levels hit record rise; UN warns more than 14 million people could lose their homes
For Mumbai, the risks are compounded by land subsidence and saltwater intrusion, which can contaminate freshwater aquifers and coastal wells. Storm surges could further put pressure on sanitation, housing and transport infrastructure, it says. (Image: Amit Chakravarty)
Mumbai is among the South Asian megacities facing a growing risk of permanent inundation from rising sea levels, with a new United Nations report warning that more than 14 million people across the region could be at immediate risk of losing their homes.
The report, Challenges related to sea level rise and ways and approaches to address, submitted to the UN General Assembly on August 31, identifies Mumbai, Kolkata and Dhaka as cities where the consequences of rising seas could be measured not just in economic losses but in large-scale human displacement.
The report says global sea levels rose at a record rate of 5.9 mm in 2024, compared with an average annual rise of 4.7 mm between 2014 and 2023. It projects at least 0.5 metres of global sea level rise by 2100 even under aggressive emissions reduction scenarios. Under worst-case scenarios involving instability of the West Antarctic ice sheet, the rise could reach up to two metres, making extreme sea-level events an annual occurrence in coastal areas.
“In the low-lying deltas of South Asia, in cities such as Kolkata and Mumbai in India, and Dhaka, the defining impact is human displacement, with more than 14 million people at immediate risk of losing their homes to permanent inundation,” the report says.
For Mumbai, the risks are compounded by land subsidence and saltwater intrusion, which can contaminate freshwater aquifers and coastal wells. Storm surges could further put pressure on sanitation, housing and transport infrastructure, it says.
The UN assessment is also consistent with warnings in Mumbai’s Climate Action Plan (MCAP), released by the Brihanmumbai Municipal Corporation (BMC) in 2021. The plan had projected that 80 per cent of Mumbai’s island city could be submerged by 2050. It also estimated a sea-level rise of 0.1 to 0.3 metres along Mumbai and 11 other Indian coastal cities over the next three decades.
Climate scientist Raghu Murtugudde, emeritus professor at the University of Maryland and visiting professor at IIT Bombay, said Mumbai’s exposure was heightened by its geography and changing weather patterns.
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“Mumbai is surrounded by the Arabian Sea on three sides,” he said, adding that warming of the Arabian Sea was contributing to changes in sea surface temperatures and intensifying extreme rainfall and heat events.
BMC rainfall data indicates that the city is already experiencing changes in extreme rainfall. The average rainfall recorded during very heavy rainfall events has increased from 132 mm to 182 mm over the past six years. In the last decade, Mumbai has recorded 28 spells of very heavy rainfall lasting four hours or more.
Despite a forecast of below-normal rainfall this year, the city recorded three instances of more than 100 mm rainfall within 24 hours during the first eight days of July.
“Alongside erratic rainfall, high tidal waves also contribute to coastal flooding. The city’s rainfall pattern is changing drastically, while at the same time sea levels are rising,” Murtugudde said.
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The UN report calls for climate-risk assessments to give greater weight to human displacement and social impacts, alongside financial and infrastructure losses. It warns that nearly 500 million people globally live in low-lying coastal zones where rivers meet the sea, making investment in adaptation, resilience and loss-and-damage measures increasingly urgent.
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 More
