Coastline in crisis | Six experts give us their climate manifesto for Mumbai
The citizens’ manifesto is a roadmap for policymakers and spans five vital topics each a cornerstone in the battle against the adverse effects of climate change
Emblematic of numerous coastal cities globally, Mumbai confronts a growing onslaught of climate-induced challenges. These include the peril of rising sea levels, increasingly severe monsoon seasons, vanishing coastlines and the intensifying urban heat island effect, all of which pose a significant risk to its residents.
Last month, at the invitation of the deputy chief minister of Maharashtra, delegates from the Japan International Cooperation Agency (JICA) were taken on a tour of some of Mumbai’s waste treatment plants and talked about the city’s efforts to mitigate climate-related adversities. It was announced that JICA would help create a climate master plan for Mumbai.
"This effort will aim at developing a master plan which includes steps aimed at tackling risks associated with climate change in the future," said P Velrasu, additional municipal commissioner of the Brihanmumbai Municipal Corporation (BMC). The master plan being prepared by JICA, he said, would be comprehensive with all the critical components necessary for climate proofing the city.
The components of climate proofing the city from the risk of floods, for instance, involve enhancing green cover and implementing “sponge city” infrastructure, i.e urban development designed to absorb and reuse rainwater, reducing flooding and enhancing water sustainability by integrating green spaces, permeable surfaces, and innovative water management systems.
The plan itself would take a couple of years to be developed, for which the BMC will make its data readily available.
We reached out to five experts who shared their wishlist of what should make it into the climate master plan. The citizens’ manifesto, as it were, is a roadmap for policymakers and spans five vital topics — coastal climate resilience with an emphasis on flood management, water and infrastructure, urban planning and green cover, mangroves and wetlands, and waste management — each, a cornerstone in the battle against the adverse effects of climate change.
Coastal climate resilience
A city that regularly grapples with monsoon-induced flooding needs innovative flood management strategies. Mumbai's rapid population growth projected to double by 2050 to 40 million, coincides with an alarming increase in global mean surface temperatures. This demographic and climatic intersection demands immediate attention to the city's coastal climate resilience, especially in light of rising sea levels and increasing extreme weather events.
Dr Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology and Intergovernmental Panel on Climate Change (IPCC) author, emphasises the urgency of the situation. "Mumbai's extensive coastline and low-lying areas make it particularly susceptible to sea level rise, a phenomenon exacerbated by the thermal expansion of warming ocean waters.”
A three-centimetre rise in sea level per decade might seem infinitesimal, but it translates to a significant loss of land, Koll said. He also projected that the rate could reach 5–7 cm per decade if carbon emissions continue unchecked.
Addressing Mumbai’s vulnerability to coastal flooding, cyclones, and storm surges, Koll advocated for the modernisation of Mumbai's drainage and water management systems in the context of developing a comprehensive climate master plan for the city.
Noting a significant shift towards fewer rainfall days but more instances of extreme heavy rain, he also highlighted the imminent threat of compound floods in Mumbai, where heavy rains, high tides, and elevated sea levels converge. “Such compound floods have the potential to submerge large parts of Mumbai, at least for several days,” he said, adding that the Arabian Sea's increased cyclonic activities could further exacerbate these events.
Thus, robust, climate-resilient infrastructure such as the construction of seawalls and storm surge barriers can significantly mitigate the impact of storm surges and rising sea levels on coastal communities, he said.
"Our natural defences against floods are degraded," he said, citing the example of the Bandra Kurla Complex built on mangrove land and the Mithi river being choked and reduced due to development.
Thoughtful urban planning and innovative engineering solutions need to go hand in hand. “The city must adopt a multi-faceted approach that integrates early warning systems, disaster risk reduction, and community engagement," he said. This strategy, coupled with the preservation and restoration of natural ecosystems like mangroves and floodplains is crucial for enhancing Mumbai's resilience against climate-induced challenges.
Collaborative efforts among government bodies, urban planners, scientists, engineers, and community organisations are a must. “The city's future, prosperity, and even survival depend on its ability to adapt and rise above the rising seas,” he said.
Water and infrastructure
Ironically, Mumbai also faces a pressing challenge of water infrastructure.
Nikhil Anand, assistant professor of anthropology at the University of Pennsylvania, who also consulted on the Mumbai Climate Action Plan in 2021, identified three key areas of focus to reduce the vulnerability of the city's residents, in particular those living in slums, who face the brunt of the issue.
First, upgrading and extending the drinking water supply to every citizen. “If adaptation is about reducing vulnerability, then reducing vulnerability in the everyday life of most of the city's residents is of utmost importance," he said. This step is fundamental in enhancing the resilience of Mumbai's most vulnerable communities.
Second, diversifying water sources. Cautioning against an over-reliance on traditional sources like Tansa and Vaitarana lakes, Anand suggested exploring existing water sources within the city, such as BMC wells. This would also decrease resorting to energy-intensive and expensive options like desalination that pose environmental concerns.
“To combat flooding, there is a need for a blend of grey and green infrastructure. Expanding and extending green spaces, including riverbanks, khadis, creeks, and wetlands, can significantly increase the city's capacity to retain rainwater, reducing the need for larger drainage systems,” Anand said.
Retention ponds, bioswales, and other percolation technologies further, can “alleviate the burden on the city's stormwater and drainage systems by managing runoff effectively,” he said.
Third, addressing water pollution. Most of the city’s sewage is untreated and discharged directly into bodies like the Mithi river. “Upgrading sewage treatment to include secondary and tertiary technologies before releasing it into the sea, to prevent the pollution of marine ecosystems and the subsequent impact on the city during the monsoon is critical to ensure climate resilience," Anand said.
Green cover and urban planning
Urban infrastructure must go beyond mere resilience, and aim for antifragility in the face of climate change.
Ronita Bardhan, associate professor at Cambridge University, teaching architecture and urban studies, highlighted the concept of antifragility, and asserts that Asian cities like Mumbai need to re-evaluate their urban planning strategies. "Antifragility is about becoming stronger in the face of adversity, not just bouncing back," Bardhan said.
Urban greening, for example, helps mitigate climate-related challenges like urban heat island effect. Antifragile strategies require a trauma-informed approach, integrating urban green infrastructure not only to address climate stress like urban flooding but to also reduce inequalities in the city. "Climate-sensitive plans should first identify the inequality in the spatial distribution of different forms of green and then apply a co-benefit approach," she said.
Bardhan further notes the importance of designing multi-use green infrastructure in space-constrained cities like Mumbai.
Echoing similar sentiments, Hitesh Vaidya, former director, the National Institute of Urban Affairs (NIUA) under the ministry of housing and urban affairs, shared the importance of strategic, integrated urban planning.
Climate action plans, land-use master plans, and transportation schemes should not function in isolation, he explained but should have a holistic perspective that transcends city boundaries.
Together, Bardhan's and Vaidya's insights provide a comprehensive framework for Mumbai's journey towards becoming a climate-sensitive, anti-fragile city. Their emphasis on integrating green cover with urban planning, while addressing social inequalities and enhancing resilience, forms a pivotal part of the city's climate action strategy.
Mangroves and wetlands
Mangroves and wetlands are critical ecosystems that offer natural protection against coastal erosion and floods, while also fostering biodiversity.
N Vasudevan, a retired IFS officer and former principal chief conservator of forest (Mangrove Cell), Maharashtra forest department, and national coordinator for the Green Climate Fund, acknowledges Mumbai's success in retaining substantial greenery, despite its dense population. “The city and its surroundings have shown an increase in mangrove cover in recent years,” he says, attributing this growth to two reasons: The notification of mangroves as Reserved Forests following a Bombay high court directive in 2005, and the establishment of the Mangrove Cell in 2012 and the Mangrove Foundation in 2015. The Mangrove Foundation is an autonomous body of the state government which works on mangrove protection efforts and marine biodiversity conservation initiatives.
Yet, there is a disparity in conservation efforts between government-owned and privately-owned mangroves, Vasudevan said. “Despite legal protections, mangroves on private land face greater threats. The private mangroves of Mumbai deserve serious attention now," he said.
To address this, he proposed schemes that incentivise the conservation of private mangroves. “This could include offering Transfer of Development Rights (TDR) by the municipal body, voluntary land surrender in exchange for compensation, or developing eco-tourism projects under a lease or revenue-sharing arrangement,” he said. Another approach could be to explore carbon credit opportunities for preserving blue carbon ecosystems. A balance of incentives and penalties is ideal as private owners who are unwilling to engage in conservation efforts should bear the responsibility for destruction and restoration costs.
These proposals reflect a nuanced approach to mangrove and wetland conservation as they blend legal protection with economic incentives to balance the imperatives of urban expansion against climate change.
Waste management
Swati Singh Sambyal, an international circular economy expert in waste management and environmental sustainability, outlines a critical strategy for tackling waste-related challenges in Mumbai.
Highlighting the impact of waste on greenhouse gas emissions, especially methane, Sambyal said local policies that align with circular economy principles are needed. “We need policies that encompass a just transition, including the informal sector, with stringent penalties for non-compliance," she said.
Simply put, centralised and decentralised waste management systems need to be blended. "For residential societies with high segregation rates, in situ treatment of wet waste, including composting, is crucial. For the dry fraction, effective sorting and channelisation are key,” she explained.
To reduce harmful waste disposal practices, Sambyal proposes financial deterrents. "Introducing a landfill and incineration tax is essential to discourage waste burning and dumping," she said. Additionally, she suggests restructuring municipal concessionaire agreements to promote segregated collection and processing by implementing a tipping fee.
Crucial to the success of these initiatives is behavioural change. “Focusing on behaviour and citizen science is vital. Mumbai, as an educational hub, can leverage academic institutions and students to drive awareness and cement lasting behaviour change,” said Sambyal.
She also highlights Mumbai's vulnerability as a coastal city, stressing the risks posed by inadequate waste management. "If we overlook waste management, the consequent leakages into air, water, and soil can wreak havoc, from exacerbating flooding due to blocked drains to deteriorating air quality," she warns.
Mumbai's ambitious climate action plan and its challenges
The Mumbai Climate Action Plan (MCAP) unveiled in August 2021 under the previous Maharashtra Vikas Aghadi (MVA) government remains a crucial document for shaping Mumbai's response to climate challenges. It outlined a series of ambitious goals including a 2050 net zero target for Mumbai, and measures tailored to the city's unique needs and vulnerabilities across six sectors: Sustainable waste management, urban greening and biodiversity, urban flooding and water resource management, building energy efficiency, air quality and sustainable mobility.
“The MCAP is very much still being considered and implemented as the nodal document for climate action for the city,” a senior official from BMC's environment department said.
The BMC initiated a climate budget provision process for Mumbai, reflecting a tangible step towards actualising the MCAP's objectives. "All BMC departments have been given a form to identify the climate threats they are witnessing and the budget allotment they would require based on solutions provided by MCAP for implementation," the official explained. Once the departments submit their estimates, a detailed budget dedicated to climate action will be collated and presented as part of the 2024-25 annual budget of the BMC.
However, the implementation of the MCAP is not without its challenges. The official acknowledged the slow pace of progress and attributed it to the complexities of interdepartmental coordination and the involvement of multiple stakeholders. “On the current implementation side of the MCAP, it is slow and will take time as interdepartmental coordination is key.”
Badri Chatterjee is head, Communications (Climate & Energy) at Asar Social Impact Advisors, a research and communications organisation that works on social and environmental issues
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