Manori had slowed down for its afternoon siesta after a morning of fishing and farming when word spread, in January this year, that government officials were inspecting the beach. Locals hurried to its rocky shore. There, the officials confirmed it. The site was earmarked for Mumbai’s first desalination plant.Until then, residents had only heard murmurs of the project. The survey raised more questions. Their own research, and a conversation with their local corporator, led them to a desalination plant in Chennai. Worried villagers from the Manori-Gorai-Uttan belt pooled money to fly in two fishermen from the southern coast to hear what had happened there. The meeting confirmed their fears.“The fisherfolk who were based around Chennai’s Nemmeli desalination plant told us how they had faced sea erosion and pollution. We mapped our boats, sought information from authorities and realised that our fish catchment and livelihoods could be similarly affected by the new desalination plant in our backyard,” said Switsy Henriques, a local resident and president of the Gorai Villagers Welfare Association.Posters against the plant now line the roads of these once-quiet fishing villages. The anger that had been building for months came to a head on October 19, when over 800 villagers and fishermen thronged the collector’s office seeking cancellation of the project until discussion.The plant will sprawl across 29 hectares of suburban collector’s land handed over to the Brihanmumbai Municipal Corporation (BMC). Its first phase, with a capacity of 200 million litres a day (MLD), is slated to start operating by December 2029 and is expected to meet the daily needs of up to 15 lakh people.With a strong El Nino pattern bringing drought across Maharashtra this year and raising concerns over Mumbai’s own water shortfall, the BMC has begun geotechnical work in Manori, including a soil survey. For a community that has always lived off the sea, that has been cause for alarm.TWO DECADES IN THE MAKINGA desalination plant removes salt and debris from seawater to make it fit to drink. Such plants are used widely in West Asia and in coastal countries like Singapore, where desalination has earned the name “fourth national tap”.Story continues below this adIndia’s first large-scale desalination plant was commissioned in Chennai in 2010. Manori will be BMC’s and Maharashtra’s, first. But the idea of desalinating Mumbai’s seawater goes back to the 2000s.In 2007, a high-level committee appointed by the state government suggested setting up desalination plants in Mumbai. During the acute water crisis of 2009, the BMC brought in external agencies to study feasibility and prepare a road map. It looked at a 100 MLD plant at Versova or at Navy Nagar in Colaba. High costs and land acquisition worries pushed it to cancel the proposal in 2016.The project was revived in 2019, after the then Environment Minister Aaditya Thackeray showed interest. In June 2021, the BMC signed a memorandum of understanding with Israel’s IDE Water Technologies to prepare a detailed project report for the plant. The same company would go on to win the contract four years later.In 2023, the civic body floated a Rs 3,520-crore tender to build, operate and maintain a plant in Manori for 20 years. The response was weak. Deadlines were extended several times, and in August 2024, with only one bidder in the fray, an Israel-based company, the BMC cancelled the tender.Story continues below this adA fresh global tender followed in 2025. In December 2025, the contract went to a joint venture of IDE Technologies and GVPR Engineers Limited, to build the facility and maintain it for 20 years after commissioning. The plant is expected to cost Rs 4,077 crore.Manori is not the city’s only plan. As soil survey work begins there, the BMC has also earmarked land in Versova for a second 200 MLD plant. Together, at full capacity, the two plants are projected to add 600 MLD to Mumbai’s water supply. The state government is banking on them to reduce the city’s dependence on rain and bridge its current shortfall of 550 MLD of drinking water. Fishing boats wait out low tide on the Manori shore in north Mumbai. Most families here depend on fishing, and they fear the city’s first desalination plant, coming up on a hillock nearby, will harm fish breeding and their catch. (Express photo by Sankhadeep Banerjee)FROM SEA TO TAPThe Manori plant will be built to treat up to 400 MLD of seawater, though the first phase aims for 200 MLD a day. It will use reverse osmosis. “This will be the same RO technology used in our home water purifiers, except that the scale of this project will be much larger,” an official explained to this newspaper.Spread over 29 hectares atop a hillock, the plant will have tunnels to draw in seawater and send waste back to the sea, a pumping station to pull the seawater in, and two tanks to store the treated drinking water.Story continues below this adSeawater will be drawn in through a zig-zag intake and then through screens that catch large debris. It will then be cleaned of sand, silt and other impurities, and passed through very fine filters that remove small microorganisms. High-pressure pumps will then force it through two rounds of reverse osmosis. The first strips out most of the salt. The second polishes the water further into high-quality drinking water. Finally, minerals are added, the water is disinfected and pumped into the storage tank.From there, it will travel through a 7.2-km tunnel to Charkop and Kandivali’s Mahavir Nagar in the western suburbs. The BMC has awarded the Rs 2,241-crore contract for the tunnel to Afcons Infrastructure.The brine, the salty waste left behind, will be collected in a tank where it is neutralised. It will then be released into the sea through a pipe fitted with 15 diffusers, which spread it out. The pipe that draws seawater in will reach about 2.3 km out to sea, and the one that sends brine out about 2.4 km, both measured from where they meet the shore. The BMC says both will be built by tunnelling, without blasting, so the seabed isn’t disturbed. But none of this has eased the fears along the coast.‘WHAT HAPPENS TO THE FISH?’The site, now barricaded behind blue tin sheets, was once grassland where cattle grazed, fisherfolk dried their catch and children played. Its view of the Manori coast from a small hillock also made it a popular tourist spot.Story continues below this adBut nostalgia is the least of the locals’ worries. Majority of people here depend on fishing, directly or indirectly, for a living. They fear the plant will harm marine life and fish breeding, and eventually their catch. The same worry runs through Gorai, Uttan, Pali, Dongri and Chowk, all within 10 km of the site.Francis Lakri, whose family has fished off Manori for centuries, said fish that come to the coast to lay eggs could be disturbed.“Many fish like eels and mudskipper come along the coast for breeding. But this desalination plant could disturb the quietude that the fish require to breed as well as increase salinity because of which catchment could be permanently killed. We fear that the impact will be felt not only in Manori but along the entire belt from Versova to Arnala over time,” Lakri told The Indian Express.Locals said the catch at risk ranges from Bombay duck, pomfret and eels to pricier varieties like lobster.Story continues below this adBernard D’mello, working president of the Akhil Maharashtra Macchimar Kriti Samiti (AMKS), said, “The extremely saline discharge called brine will be released back into our sea, after the treatment. But this waste brine will be dense, and eventually settle along the coast with time. With time, this will prevent all types of fish from coming along the coast. Expensive catch like lobsters and crabs which come on the rocks, prefer to come there when there is no disturbance. The constant activity along the shores stands to affect all this.”“Owing to sea pollution, we are already compelled to fish in the deeper seas — sometimes for eight to ten days at a stretch. We are concerned that such facility will further affect our economy. We are not saying that the change will be immediate, but with time, this can gradually kill the catch,” he added.Leo Colaso, a fifth-generation fisherman from the area and president of the Maharashtra Machimaar Kriti Samiti, said Manori, Uttan and Gorai are home to over 20,000 fishing families who depend mainly on fisheries. “The water for the desalination facility will be drawn from our coast. But what happens to the fish? The smaller baby fish, eggs and fish breed will also be pulled in owing to the suction in their inlet pipe. Won’t this directly affect us fisherfolk?” he said.According Colaso, fishermen here typically work 240 earning days, making up to Rs 3,000 a day each, their hours set by the tides. On other days, they tend to their nets and boats..Story continues below this ad“We are self-sufficient and have been doing their work for generations. But this project has left us all worried. Look at the water now, it’s still. But the constant movement from the plant will increase disturbance to water and permanently hamper fish catch. What is the future for our younger generation who will come to work here?” Colaso said.Henriques said the losses would not stop with fishermen. Transporters, restaurateurs and exporters also stand to lose.Farmers are worried too. The villages around Manori have fertile farmland. “We have paddy fields and crops including brinjals, mangoes, chilis, pumpkins etc on our farmlands. If the waste effluent from the plant increases salinity, this is bound to affect our crops too,” said Desmond Paul, a Gorai-based farmer and president of the Gorai Shetkari Vikas Sanstha, a collective of farmers from Gorai.Lakri also questioned the need for such an expensive plant when, according to BMC’s own report, 34 per cent of the BMC’s daily drinking water supply is lost. “Can’t the lakhs of litres of water being lost to theft and leakages in old pipelines be repaired instead? Instead of polluting the sea water, the BMC should look into projects to develop dams and store rainwater,” Lakri said.Story continues below this adTHE BMC’S ANSWERAt a meeting last week, Abhijit Bangar, Additional Municipal Commissioner (Projects), said the plant had specific features to protect marine life from harm. “The intake heads are situated below deep low-tide levels to minimise impact to marine species. Additionally, the system is designed with an allowed velocity at the intake head of