A preliminary survey by the CSIR–National Institute of Oceanography (NIO) has revealed significant environmental impacts from the sinking of the container ship MSC Elsa 3 off the Kerala coast on May 25, 2025. The assessment, carried out between July 25 and August 21 aboard the research vessel Sagar Sampada, reported the discovery of a dead and deformed marine turtle at the shipwreck site, raising concerns about damage to marine biodiversity.
The survey found that the oil slick in the area had disintegrated into smaller fragments due to heavy monsoonal winds and currents. A large patch of floating oil film was also observed drifting toward coastal regions, carried by wave action.
Researchers noted intense coastal upwelling along the southwest coast, accompanied by the presence of high-salinity Arabian Sea water masses. The water column across several coastal stations—including Kozhikode, Munambam, Kochi, Alappuzha and Colachel—was found to be more oxygen-depleted than other surveyed locations, indicating the influence of the oxygen minimum zone (OMZ) in the southeastern Arabian Sea.
The survey recorded an abundance of gelatinous plankton, with blooms particularly prominent along the Kollam coast and further north. These blooms were widespread in coastal stations at depths of 10 m, 20 m, 30 m and 50 m at Kochi, Alappuzha and Kollam. The presence of Noctiluca blooms and bioluminescence was also reported from the Kollam–Kozhikode stretch, including an extensive bloom and surface-water discolouration off Arthunkal.
The Kerala government had commissioned the Kerala State Pollution Control Board (KSPCB) to engage CSIR-NIO for a long-term study assessing environmental damage from the shipwreck, under a project fee of ₹10 crore. The agency will also develop a comprehensive restoration strategy and review maritime regulations, emergency response protocols and liability mechanisms. The final report is expected by July 30, 2026, according to a status update submitted by the KSPCB before the Principal Bench of the National Green Tribunal (NGT).
The NGT Bench, comprising chairperson Prakash Shrivastava and expert member A. Senthil Vel, observed that the incident violated provisions of the Biodiversity Act, 2002; the Water (Prevention and Control of Pollution) Act, 1974; and the Environment Protection Act, 1986. The tribunal had taken suo motu cognisance of the matter based on reports of containers drifting towards Kerala’s coastal regions following the sinking.
