La Nina likely to aggravate Goa's plastic waste menace

Time of India

04-06-2025

Panaji
: A silent drift unfolded off Goa's coast between March 20 and April 10 this year. Pink and red specks began dotting satellite images — not signs of marine life, but clusters of floating plastic.
Over a 10km-long stretch along the shoreline, these clusters map a grim and growing reality: Goa's seas and rivers are turning into plastic tides.
While alarming, a deeper oceanographic force could intensify this problem. A new study by WWF India suggests that currents influenced by La Nina — a large-scale climate pattern that alters global weather, along with the northeasterly monsoon winds, could push floating plastic debris into Goa's nearshore and estuarine waters.
'La Nina strengthens the northeasterly monsoon winds over the Indian subcontinent. This, in turn, intensifies westward surface currents in the northern Arabian Sea,' said G Areendran, director, tech for conservation, WWF India. 'These stronger currents can carry floating plastic toward Goa's coast.'
'Once near estuaries like the Zuari, Mandovi, and Talpona, the debris can get trapped and even recirculate into the coastal zone, especially during dry winter months when rivers discharge less freshwater.'
Areendran and his team are leading an ongoing WWF India study under the wildlife tech incubator programme of the Centre for Wildlife Studies, funded by the Ashraya Hastha trust. The project, titled remote sensing and machine learning-based detection of floating offshore plastic debris in coastal Goa, combines open-source satellite data with machine learning to identify plastic debris in coastal waters. Researchers aim to create a WebGIS dashboard by Aug 2025 for real-time plastic monitoring.
So far, the team has tracked floating plastic till April. The data shows troubling concentrations within 10km of Goa's shore, especially near Panaji, Mormugao, and Margao. These clusters often form in convergence zones — areas where winds and currents meet and trap surface debris.
Some of the heaviest plastic build-up was found near the Mandovi and Zuari rivers. These rivers drain highly urbanised areas — including Panaji and Mormugao — and carry untreated plastic waste directly into the sea.
'In February, heatmap analysis showed dense clusters of plastic near the Zuari estuary and Panaji. The Mandovi river, being the largest in Goa, contributes significantly to plastic accumulation near Miramar beach,' said Areendran.
Further north, moderate to high debris levels were recorded offshore near Calangute, Tivim, and Pernem — areas that experience high seasonal tourist footfall and storm-water runoff.
In South Goa, plastic tended to accumulate off Betul, Talpona, and Canacona, where swirling tidal currents create circular flows that trap floating waste.
'River-borne plastic is a key driver in how and where debris gathers along the coast,' Areendran added. 'Even the inland hinterlands are now showing plastic presence in coastal waters, pointing to unregulated waste flowing through smaller rivers and drains.'
Goa may be India's smallest state, but it generates the highest per capita plastic waste in the country. According to the Central Pollution Control Board (CPCB), Goa produced nearly 12kg of plastic waste per person annually in 2019-20.
Tourism, one of the state's key economic engines, also contributes significantly to the problem. A study by the Central Marine Fisheries Research Institute (CMFRI) found that Goa's most popular beaches — Calangute, Anjuna, and Baga — recorded the highest levels of plastic litter in the country.
At peak levels, plastic waste reached up to 25g per metre of beach, with a total litter density of over 200g per sqm.
WWF's current project is not just focused on mapping the pollution. The initiative aims to support the protection of Goa's critical coastal habitats. These include nesting grounds for the Olive Ridley turtle and marine biodiversity zones already under pressure from microplastics and tourism-driven waste.
Researchers hope the study will help policy makers act since without timely intervention, Goa's scenic coastline — once a magnet for biodiversity and clean tourism — risks becoming a permanent dumping ground for floating plastic.