Deonar's rehabilitation demands a sequenced intervention — one that treats methane mitigation, coastal restoration, and carbon revenue not as ancillary benefits, but as integral to the framework itself
The Brihanmumbai Municipal Corporation (BMC) recently floated an INR 2,368 crore tender inviting bids to close India’s oldest dumping ground, Deonar, over the next three years. Operating continuously since 1927, the landfill spans 311 acres in the city’s eastern suburbs. The site receives an estimated 4,000 tonnes of waste per day, accumulated over nearly a century into a mound that now rises 40 metres, equivalent to a 13-storey building. The waste is typically untreated, making its environmental hazard more significant than landfill volume alone would suggest.
As of 2026, the Maharashtra Coastal Zone Management Authority (MCZMA) has cleared the site for rehabilitation on 124 of the 311 acres, with the project awaiting approval from the Bombay High Court. However, the details of the clearing method and the standards to be upheld to ensure safe rehabilitation remain limited. Experts have received the three-year cleanup timeline with scepticism, noting that making the land fully habitable will require partial scientific closure followed by several additional years of biomining — in which living organisms such as bacteria or fungi are used to extract metals from waste — along with bioremediation, which employs similar microorganism-based processes to treat waste that can then be partially converted into energy and construction materials. For this purpose, the BMC is considering a waste-to-energy plant alongside the rehabilitation project. While both have their purposes, neither end use resolves the public health questions that any intervention at this site must address.
Yet alternatives exist that provide essential infrastructure to minimise public health risks, mitigate post-closure toxic emissions rather than simply capping them, and sustain the economic productivity of the land in question.
The public health argument attached to both current proposals has a concrete local precedent. According to BMC data, M East Ward, where Deonar is located, reports low life expectancy and a high prevalence of tuberculosis. Therefore, any intervention that adds combustion or accelerated decomposition to this environment warrants proportionate caution.
Mindspace demonstrates that subsurface gas migration can persist long after surface-level remediation is declared complete. Without gas capture, Deonar risks repeating the same pattern after closure — subsurface decomposition continuing to generate methane and other gases long after the site is officially shut.
The trajectory of the Malad dumping ground, officially closed by the BMC in 2002, illustrates why. The Malad dumping ground was reclaimed to become what is today known as Mindspace, one of Mumbai’s largest IT parks. The release of pollutants, including methane, hydrogen sulphide, and mercaptans from the former dumpsite has caused documented damage to property and electronic equipment in the area. More importantly, leaching pollutants continue to pose significant health risks, causing chronic problems in and around Mindspace. Experts fear that this leaching will continue for over half a decade. Mindspace demonstrates that subsurface gas migration can persist long after surface-level remediation is declared complete. Without gas capture, Deonar risks repeating the same pattern after closure — subsurface decomposition continuing to generate methane and other gases long after the site is officially shut.
Across much of the world, landfills continue releasing methane for decades after closure, and closure and capping are frequently mistaken for mitigation. The Malad Mindspace experience shows that this is not a theoretical risk in Mumbai's context. With two crore tonnes of legacy waste and a compressed work calendar, the timeline for safe rehabilitation at Deonar extends well beyond what current approvals cover.
The waste-to-energy proposal also carries parallel concerns. Such plants emit toxic by-products, a matter contested by public health experts, particularly when such plants are sited adjacent to densely populated areas rather than designated industrial zones. The question, therefore, is whether there is an approach that addresses public health risks rather than adding to their complexity.
The Deonar site sits adjacent to Thane Creek, the existing mangrove cover, and the Thane Creek Flamingo Sanctuary. At least 60 percent of the remaining land not allocated for rehabilitation could be directed toward mangrove afforestation. Mangroves reduce toxic air pollution, benefiting both the rehabilitation zone and adjacent slum settlements. Since the land is state-owned, afforestation can be carried out via state-designated agencies, keeping carbon finance revenues within urban public streams.
The proposal for the closure of Deonar dumping ground pairs afforestation with landfill gas capture. Landfill gas (LFG) is composed of roughly 50 percent methane and 50 percent CO₂. Methane is at least 28 times more potent than CO₂ at trapping heat over a 100-year period. Gas capture must therefore be a core component of both the rehabilitation and afforestation plan.
Since its closing in 2012, the Jardim Gramacho restoration in Rio de Janeiro has been transforming what was once Latin America's largest landfill into an active climate-mitigation site. Following closure and capping, the installation of a landfill gas capture system and large-scale mangrove restoration dramatically reduced methane emissions while restoring coastal ecosystems along Guanabara Bay. The transformation followed a clear sequence: scientific closure first, gas capture second, and mangrove planting across stabilised coastal sections third.
The project avoided an estimated 850,000 tonnes of CO₂e annually, demonstrating that legacy waste sites can be stabilised in ways that simultaneously address methane emissions and restore ecological function. Biocovers placed over capped waste further reduced fugitive emissions, while mangrove root systems stabilised sediment and contributed to blue carbon accumulation. The marshy, tidal-adjacent portions of Deonar that are unsuitable for built development are precisely where this sequencing applies.
A closer precedent exists within Mumbai itself. A legacy landfill at Gorai, in the city’s western suburbs, was closed and retrofitted with a gas capture system comprising 40 engineering-designed extraction wells, converting captured methane into electricity fed to the national power grid. To finance the project, the implementing agency secured carbon co-financing covering 56 percent of the total capital cost, in exchange for a portion of the project’s expected Certified Emissions Reductions generated under the Kyoto Protocol’s Clean Development Mechanism (CDM). Registered as a CDM project in 2010, it became India’s first landfill closure of its kind. The BMC’s INR 26 crore in earnings from carbon credit financing established a replicable proof of concept: that the scientific closure of a legacy dumpsite can generate meaningful urban revenue alongside its environmental outcomes.
A credit accruing framework at Deonar would generate verified emission reductions eligible for sale to institutional buyers in India’s domestic Carbon Credit Trading Scheme (CCTS) and to international voluntary market participants.
Similarly, inception work on a coastal mangrove carbon finance project in Gujarat, developed for tidal wetland restoration, provides directly applicable evidence. The carbon sequestration potential across approximately 2,997 hectares of mangrove plantation in coastal Gujarat is estimated at around 1.1 million tonnes of CO₂ equivalent over a 30-year crediting period. Mangrove plantations qualify as an afforestation practice under the Kyoto Protocol, and carbon finance generated through voluntary markets can contribute to state-level carbon neutrality goals.
These precedents lay the groundwork for Deonar. In the decade since the success of these projects, India's carbon market framework has evolved to the point where Deonar's credits could be hosted within its domestic voluntary market.
Deonar presents a viable opportunity to facilitate participation in India’s evolving carbon market. A credit accruing framework at Deonar would generate verified emission reductions eligible for sale to institutional buyers in India’s domestic Carbon Credit Trading Scheme (CCTS) and to international voluntary market participants.
Gas capture infrastructure at Deonar could generate renewable energy or flared-methane credits, thereby substituting for the waste-to-energy plan while reducing toxic emissions. Additionally, mangrove restoration above stabilised coastal sections could generate blue carbon credits under an internationally recognised standard. With state ownership of the land, these revenue streams would accrue within urban public finance. Mumbai’s natural carbon sinks are already widely recognised as insufficient to offset the city’s greenhouse gas emissions.
In light of the recent Supreme Court order permitting the felling of 45,000 mangroves for Mumbai’s ambitious coastal road extension, directing Deonar's coastal and ecological characteristics toward a restoration-led approach is a policy avenue that runs in parallel with remediation already underway — and one that turns a long-standing environmental and social liability into a measurable urban asset.
Diya Shah is a Research Assistant with the Centre for Economy and Growth at the Observer Research Foundation.
Dhaval Desai is a Senior Fellow and Vice President at the Observer Research Foundation.
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Diya Shah is a Research Assistant at ORF’s Centre for Economy and Growth. Her work explores developments in climate finance as part of a broader, ...
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Dhaval is a Vice President - Platforms and Communities at Observer Research Foundation, Mumbai. His spectrum of work covers diverse topics ranging from urban renewal ...
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