Mumbai: A citizen initiative, being implemented in Versova, has proposed to install 24 low-cost net-filters across a network of streams entering Versova Creek, in the western suburbs, to free the water body of floating plastic and other solid waste.
A trial run conducted over three days in June, between June 23 and 25, in Kavtya Khadi, one of the Creek’s tributaries, collected 483kg of waste using two net-filters placed alongside each other.
A single net-filter is made using two 20-ft long fishing nets. These were then suspended in the khadi (creek) at a chosen location during high tide. The filter works exactly like a ‘dol’, an indigenous fishing device shaped like a tapering bag, which catches the waste (or fish) as the tide recedes.
The project, called New Catch in Town, is being implemented by a community of architects, researchers from Indian Institute of Technology Bombay’s Humanities and Social Sciences department, environmentalists, along with indigenous Kolis of Versova Koliwada who have fished in the Creek for generations.
Versova and Juhu together generate the most trash among Mumbai’s beaches, accumulating as much as 45 to 130 metric tonnes (45,000-130,000kg) every day, and making up more than a third of the total beach waste collected from across the city.
The project could potentially save the Brihanmumbai Municipal Corporation (BMC) lakhs of rupees annually on beach cleaning. In 2017, for instance, the BMC spent ₹199.72 lakh on maintaining these beaches; this ballooned to ₹829 lakh in 2021.
To clean up 35km of beachfront across Madh-Marve, Gorai-Manori, Juhu, Versova, Chimbai-Waringpada, Dadar-Mahim and Girgaon Chowpatty beaches, the BMC uses 10 beach cleaning machines, six tractor trailers, 11 trash compactors and three skid steer loaders. These require fuel and intensive labour to operate. Experts claim that net-filters could cut down the reliance on such machinery, as the main cost involved (other than making the filter itself) would be to clean these filters regularly.
“Most of this waste is coming from the Creek itself. Rather than keep cleaning the beach, we have tried to find a way to catch the waste in transit before it reaches there,” said Harpreet Bhullar, founder of the civil society group Ministry of Mumbai’s Magic, which helped fund a portion of this project.
“If we had used the net-filters for a whole month, we would have collected around 24 tonnes (in kg) of solid waste from Katvya Khadi alone. Now that we know this intervention is largely feasible, we are finding ways to scale it up in the area. Pilots are being planned in Trombay and Dharavi Koliwadas,” said Ketaki Tare, architect and co-founder of Bombay 61, an urban design think tank which led the experiment.
Vishnu Hegde, a Koli fisherman from Versova who played a key role in pilot project said that the cost of each net-filter, depending on the size and depth of the creek, would work out to between ₹1 to ₹2 lakh, and could be used for weeks at a time. “The nets are strong and can withstand rough weather,” he said.
“Once there were plenty of fish in these creeks, but now we fish there only during the high-tide in the monsoon. The rest of the year, there is only waste and we knew that ‘dol’ nets can be used as a solution,” he said.
D Parthasarty, professor at IIT-B and founder of Tapestry Research Project, a research collective which is the main funder behind this citizen initiative, commented that indigenous interventions are preferable to engineering solutions that are more expensive. “The fishers know the creek better than anyone, as they have depended on it for generations. If the BMC engages with them on the same lines as this project, it can create an alternate economy of waste recycling to support them monetarily. Over time, keeping waste out of the creek will improve biodiversity and quality of the ecosystem,” he said.
According to a report prepared by this team, which analysed the kind of waste collected during the trial run, it was noticed that plastic dominated the 483kg and made up 79% of items by number. Around 72% of the items comprised single-use and multi-layered plastic, which has little resale and recycling value.
The team proposed 24 locations on the creek’s several tributaries between Malad and Versova based on the Kolis community’s extensive knowledge of the water body. This included noting where the waste collected the most, and where it would be possible to deploy such nets based on the tides.
Though the group has not yet worked out an estimate cost for installing all 24 net-filters, they pointed out that it would be substantially cheaper than the money spent on beach cleaning by the BMC. “It can be done at half the cost, if not less. The only constraint is manpower, and of course the fishers need to see this as a viable employment opportunity if the intervention is to be sustained,” said Jai Bhadgaonkar, from Bombay 61.
In October 2020, the BMC was mandated by the NGT to install screens (made of metal, they work exactly like a net-filter) at storm-water drains and creeks across the city. The civic body floated tenders in February 2022.
“At the moment, we have installed six netted screens in the Irla Nallah in the western suburbs and they are working fine. By December 2024, the Mogra Nullah in Andheri, which empties into the Versova Creek, will also be fitted with screens. We have selected many drain outfalls to install pollutant traps and the work will be done by October,” said an official with the BMC’s storm water drains department. The city has at least 85 outfalls from creeks and storm water drains.
The usage of such filters has been a demand of environmentalists for several years. In 2018, in a reply to the National Green Tribunal as part of a Public Interest Litigation (PIL) filed by city-based non-government organisation Vanashakti, the state environment department had recommended similar interventions.