Can improving Mumbai’s natural defences reduce annual waterlogging and flooding? Yes, says this book

The fate of Mumbai, India’s bustling business capital by the sea, has always been intimately tied to the tides. Early on, British colonists saw strategic advantage in its deep-water harbour, set on India’s western coast and perfectly positioned for trade across the Arabian Sea. So, they took what had been a set of seven swampy islands inhabited by modest fishing communities and embarked on a vast project of dominion over nature. Starting in the late 1700s, a series of embankments were built and land was reclaimed, with – unsurprisingly for the times – little regard for the surrounding ecology. By 1838, Mumbai had become one contiguous peninsula, the foundation for a hub of commerce and industry that endures to this day. Further reclamations continued through the 20th century, culminating with the construction of the business district of Nariman Point in the 1970s.

The pressures of creeping urbanisation have hardly relented in the years since: between 1977 and 2017, Mumbai lost nearly two-thirds of its water bodies and vegetation. But while natural buffers against storm surges disappeared within city limits, surrounding Mumbai there remained a vast ecosystem of mangrove swamps and wetlands that have received a degree of protection.

Seen from above, Sanjay Gandhi National Park appears to embrace the city, and signs of Mumbai’s wilder surroundings often make themselves known to city-dwellers. Large flocks of flamingos descend on Navi (New) Mumbai’s wetlands every winter, with a record number delighting a locked-down city in the depths of the first Covid-19 wave in 2020. There is even the occasional leopard sighting in the outer suburbs, which keeps residents on their toes and reliably sends local media channels into a frenzy.

Unfortunately, these welcome glimpses of the region’s biodiversity disguise an urban infrastructure that is failing its citizens. Historically high rainfall has hit the city in recent years as climate change has intensified cyclones in the Arabian Sea and shifted monsoon patterns. With urban sprawl having replaced the natural wetland and riverine sponges that once stood there, streets turn into streams and floodwaters claim lives and livelihoods with worrying intensity and frequency. It is the city’s least privileged residents who bear much of the burden. The pressure looks unlikely to relent: the World Bank estimates that Mumbai will bear $6.4 billion in flood-related costs annually by 2050.

Part of the answer surely lies in upgrading the city’s creaking grey infrastructure. Mumbai’s colonial-era stormwater drains are simply not fit for purpose; renewing them is a key priority. So too is the installation of walls, pumps and floodgates to keep neighbourhoods safe. But the city’s leaders and a committed group of activists, philanthropists and scientists are also looking to emulate the likes of Singapore. Bolstering the city’s natural defences, rather than seeking simply to subdue nature like Mumbai’s colonial masters once did, is now rightly on the agenda.

Mumbai’s 2022 Climate Action Plan, a joint effort between the government, the World Resources Institute and the C40 Cities network that includes leaders like Singapore, emphasises the role of nature in addressing Mumbai’s vulnerability to a changing climate. For one, the city has made urban greening and biodiversity one of six key planks of its plan, touting the benefits of greening in reducing the urban heat island effect and improving the health and wellbeing of residents. The plan also admits that the large-scale “concretisation” of the city has exacerbated Mumbai’s monsoonal woes, acknowledging that “nature-based solutions would go a long way in reducing annual instances of waterlogging and flooding”. Looking ahead, the plan offers a detailed vulnerability analysis and a range of quantitative targets for the short and medium term.

Mumbai is also banding together with other cities to bring nature back. In 2021, thirty-one cities, from Tel Aviv and Tokyo to Mumbai and Milan, signed C40’s Urban Nature Declaration. In it, they each committed to using their city budgets and policy tools to achieve 30–40 per cent green cover by 2030, and to ensuring that 70 per cent of residents were no more than a fifteen-minute walk or bike ride from green or blue spaces.

Aaditya Thackeray, the then–Minister for Environment and Climate Change for the state, described Mumbai’s C40 commitment as core to the city’s climate action plan. “Climate change is the greatest inequity – the ones least responsible are most affected,” he said at the launch, hoping that Mumbai could be ‘a shining example of how diverse ecosystems can thrive in urban environments to achieve inclusive climate resilience for all.”

Freetown, the capital of Sierra Leone, had flood resilience in mind too when it signed the declaration, seeking to reverse the deforestation that had caused devastating mudslides in recent years. ‘“Freetown the Treetown” is our city’s ambitious plan to plant and grow one million trees over two rainy seasons,” Mayor Yvonne Aki-Sawyerr said. “But we’re not only planting them, we’re growing them – which means we’re monitoring their growth, and bringing new life to our hillsides and mangrove-forested areas.”

Lubaina Rangwala of the World Resources Institute, one of the authors of Mumbai’s climate action plan, told me that the emphasis on restoring nature to Mumbai reflected a far broader shift in thinking across different stakeholder groups in the city. “There’s a completely different conversation that is now active in the city. And it’s not only the leaders that are leading it – it’s the citizenry too, demanding changes to our post-independence love of concrete and steel. The business case for nature’s impact on health and infrastructure was becoming clearer by the day.”

Excerpted with permission from The Case for Nature: The Other Planetary Crisis, Siddarth Shrikanth, Penguin India.