A woman drains out water from her house after flooding caused by incessant rains at BIT Chawl area, Parel, in Mumbai, August 4, 2020. Photo: PTI.
A week ago, hundreds of fish and crabs washed onto Juhu beach in Mumbai. This isn’t the first time dead critters from the ocean have been on Mumbai’s beaches – because they are a symptom of the polluted waters that surround Mumbai, waters that inundate the city every monsoon, waters that are likely to keep coming back as the climate changes.
The Indian Ocean is a part of Mumbai’s framework. “Much of the city goes into the sea as it were, by way of sewage and rivers and coastal runoff,” Nikhil Anand, an anthropologist at the University of Pennsylvania, told The Wire Science.
The lives of Mumbai and its people have been moulded by the Arabian Sea for centuries. While global warming is already beginning to impact the city, its ability to tackle rising seas, extreme rainfall and storm surges were laid in the foundation stone of reclamation. Increased urbanisation and the waters around the city have played tug-of-war for centuries.
Mumbai’s tussles with extreme events and its underwater future have been modelled by both domestic and international researchers, with grim results. While real-estate development created many of the problems the city faces, and has left it more vulnerable to climate change than it was before, developments that take climate change into consideration can still help Mumbai prepare, adapt and survive.
Mumbai’s ascent as the financial capital of India – with as many people as in London and Chicago combined in an area half the size – began when it started filling in the land between its seven original islands. But even as the city as we know it came to be, problems with reclamation, mismanagement and poor law enforcement have grown.
In the various attempts to build out the city, officials have eroded beaches, destroyed mangroves, choked essential waterways and ravaged water-holding lands. Dharavi was once at the edge of the city but today it is smack dab in the middle, and teeming with people. The swanky Bandra-Kurla Complex was built on the graves of more than 600 acres of mangroves and wetlands. The Bandra-Worli Sea Link was paid for in money as well as the loss of the Dadar beach and an altered shoreline.
And apart from all of these changes, Mumbai today faces multiple threats due to human-caused global warming and climate change.
A single degree’s rise of the air’s temperature could increase its moisture-carrying capacity by 7%. With every degree, this figure is compounded. The western Indian Ocean is a warming hotspot. In addition to rising sea levels that threaten to swallow up the city, and seasonal flooding, the city must also contend with the possibility of a rare – but disastrous – cyclone. While historically the risk of cyclones on India’s west coast has been low, warmer air and warmer oceans may just make history.
There has also been a threefold rise in extreme rainfall events between 1950 and 2015, according to Roxy Koll at the Indian Institute of Tropical Meteorology, Pune. While these events have been becoming more intense and frequent, the overall quantity of rainfall has been dropping. This means intermittently heavy rainfall will be interspersed with long, dry spells. In rural areas, flooding events have even been found to be responsible for more deaths by suicide – due to distress – than droughts.
In urban Mumbai specifically, there is also the heat island effect to contend with, and with heat stress as a public health concern. Concrete absorbs and retains heat during the day and releases it in the evening. So temperatures within built-up areas have been found to be higher than in the surrounding suburbs or in non-urban areas.
Concrete is, so to speak, passive; there are many other ways in which Mumbai has been actively shooting itself in the foot.
The waters off Mumbai are warming and also becoming more polluted. With limited solid and liquid waste management, and ineffectual to boot, the city’s rivers and nullahs have turned foul. And their backflow onto the city’s beaches has deposited faecal bacteria there – more than a few of which are drug-resistant species.
At IIT Bombay, Arun Inamdar uses remote-sensing technology to study coastal waters and anthropogenic impacts. He has found that biological productivity in the seas around Mumbai is lower today than it was a decade or so ago.
For the fisherfolk, this means fewer fish to catch and a lot more by-catch that is often not consumed. “There is a considerable reduction in catch and there is a considerable reduction in some of the major species which they used to catch, you know, fishes like bombil,” D. Parthasarathy, a social scientist at IIT Bombay, told The Wire Science.
At Versova creek, several rivers meet and empty their trash-laden waters into the sea. Correspondingly, the Versova fisherfolk community has noticed a significant reduction in catch. “They say that if we go fishing in the creek, it’s more like we’re fishing out garbage,” Ketaki and Jai Bhadgaonkar of Bombay61, an organisation that works to improve community participation and craft bottom-up solutions to environmental problems, told The Wire Science.
Discussions between Versova’s fishing colony and Bombay61 gave rise to one potential solution: a net filter at the mouths of several rivers that travel through the city, collect waste and culminate at the creek. In a pilot experiment at one spot along the Oshiwara river, a filter picked up 300 kg per hectare of mostly plastic waste over 15 days. Most of it was domestic, although it also included some industrial waste like tyres, packaging material and construction debris.
Taken all together, Mumbai as a city has been becoming warmer in parts, more polluted, short on natural resources, and more vulnerable to erratic but intense rain and storms. When these changes are in turn superimposed on the city’s existing housing poverty, class divide and abysmal public infrastructure, it resembles a fertile ground to extract economic growth in exchange for exploitation and environmental abuse.
As if this wasn’t bad enough, there’s also the risk of its threats resonating with each other to become even more potent. When two extreme events occur in simultaneous or successive fashion, they create a compound extreme event that greatly amplifies risks due to each event as well as the whole. Consider, for example, a summertime heat wave followed by a drought due to delayed monsoons – or a cyclone showing up at the height of a local disease outbreak.
According to Anand, the anthropologist, an important part of this radically new ‘normal’ for Mumbai is its wetness, and which he says the city must learn to embrace. Most of its natural woes and dilemmas are the result of stopped, blockaded, over-extracted, abandoned, contaminated, stagnated, redirected and/or wasted water.
Axiomatically, most of the more practical ways to deal with the effects of climate change call to revamp the city’s water management and drainage systems, restore mangroves – its natural coastal barriers – and create designated open spaces that help absorb Mumbai’s flood waters.
Mamta Patwardhan, an architect who studies climate-related issues at the Kamla Raheja Vidyanidhi Institute for Architecture and Environmental Studies, agreed. Mumbai needs more of these natural areas, to absorb and/or hold water, especially if city officials can’t build and maintain a performant drainage system.
These areas could also serve as parks for community use and provide new habitats for urban birds and animals (the latter may in fact be inevitable). In fact, most researchers agreed on most matters – but on the matter of climate change in particular – government and local community participation were equally important. By extension, policies designed to serve the environment over the people and vice versa wouldn’t work. Also by extension, policies designed to protect real-estate and construction groups’ ‘business as usual’ might fail utterly.
For instance, the Coastal Regulation Zone rules were meant to protect fragile coastal ecosystems – but they’ve become weaker under pressure from the real-estate and development lobbies. In a city where real estate is big business, more broadly, environmental concerns have taken a backseat. Marginalised communities that have most often been the primary – or even sole – victims of environmental and climate-related issues have often been left out of the conversation.
On the other hand, Marine Drive, which was built on reclaimed land, continues to have some of the highest property values in the city even as it is threatened by sea-level rise and storm surges.
And while local and state agencies have taken studies and scientific findings into account to craft some policies that address climate change, their implementation – as has almost always been the case in India – is suffused with uncertainty.
Maharashtra published its State Action Plan on Climate Change last year, and it was almost immediately met with criticism for not addressing storms and air pollution. Today, it is not clear how it will be implemented – if at all.
Ultimately, “greater political will to actually change our urban development, urban planning strategies and focus more on preserving coastal ecosystems” is required, Parthasarathy said. Now and in the future, urban planning and development must take climate change into account.
More recently, Mumbai became only the second city in India to get its own monitoring and flood warning system developed. This Integrated Flood Warning System, or I-FLOWS, is expected to be able to provide alerts about potentially flood-prone areas based on rainfall data, tide levels, storm surges and other parameters up to three days before the event. As such, city authorities have said it will help the city prepare for extreme rainfall and stronger cyclones – particularly the consequent flooding.
In several parts of the city, pumping stations (with working stormwater drains) have made for another way to deal with floods. For example, Gazdar Bandh, in Santa Cruz, is surrounded by four nullahs that can take away stagnant water. But they are choked with garbage, leaving low-lying parts of the area to flood rapidly after a downpour.
The Brihanmumbai Municipal Corporation has installed pumping stations here to move 36,000 litres of water per second into the sea, and has also started cleaning the nullahs more regularly.
However, both these solutions, and others like them, fight the consequences of the issue and not the issue itself. For example, Gazdar Bandh floods because informal settlements sprang up in mangrove-depleted areas and waste from there entered the nullahs. But how are mangroves getting destroyed? And why did people settle down there?
Similarly, with a view to restoring natural hydrological systems, the city has a mandatory rule to harvest rainwater – but it is rarely implemented. Why is that? According to Patwardhan, the architect, residential blocks could have their own rainwater-harvesting systems that guide excess water flow into the ground.
Development that helped build the city has helped make it more susceptible to the forces of climate change. But development in a new direction, one that welcomes wetness and open spaces, has the potential to revitalise the city’s lifeblood.
Reporting for this story was supported by a grant from the Purpose Climate Lab. The Wire Science retained full editorial control.
Sukanya Charuchandra has written for The Scientist, Johns Hopkins Magazine and Firstpost. Her writing interests feature biology, medicine and archaeology.