On August 19, 2025, the Sundarbans Tiger Reserve in West Bengal officially became India’s second-largest tiger reserve following the approval of a major expansion by the National Board for Wildlife (NBWL). The board, chaired by Union Environment Minister Bhupender Yadav, sanctioned the addition of 1,044.68 sq km to the existing reserve.
Following the approved expansion, the Sundarbans Tiger Reserve now covers 3,629.57 sq km, making it the second-largest tiger reserve in India. It has moved up from seventh place, now trailing only Andhra Pradesh’s Nagarjunasagar-Srisailam Tiger Reserve, which remains the largest at 3,727.82 sq km.
The Sundarbans Tiger Reserve currently comprises a core area of 1,699.92 sq km, along with an additional 885.27 sq km of buffer zones. The West Bengal Forest Department has proposed incorporating three additional ranges—Matla, Raidighi, and Ramganga—into the reserve. This expansion would add 1,044.68 sq km to its total area. These three ranges, located in the South 24 Parganas district, are known habitats for tigers. Integrating them into the main reserve would enhance habitat management and strengthen wildlife protection efforts.
The Sundarbans Tiger Reserve, one of India’s oldest, was established in 1973 alongside the launch of Project Tiger. It also encompasses a national park that holds the status of a UNESCO World Heritage Site.
The Sundarbans is the world’s largest mangrove delta, consisting of hundreds of islands interwoven with a complex network of rivers, rivulets, and creeks. This vast mangrove forest spans both the Indian state of West Bengal and the southwestern region of Bangladesh, formed by the confluence of the Ganga, Brahmaputra, and Meghna rivers flowing into the Bay of Bengal.
The Indian Sundarbans cover approximately 4,200 sq km, while the larger portion—around 6,000 sq km—lies within Bangladesh. According to a 2014 World Bank report titled Building Resilience for the Sustainable Development of the Sundarbans, this region ranks among the richest ecosystems globally. It hosts exceptional biodiversity, including threatened species like the Royal Bengal tiger, estuarine crocodile, Indian python, and several species of river dolphin. The Sundarbans is home to over 10 per cent of India’s mammal species and 25 per cent of its bird species.
The Royal Bengal tiger has evolved remarkable physiological and behavioral adaptations to thrive in this saline, tidal mangrove habitat. These include the ability to drink saline water, a stockier and more muscular build, a coarse, shorter coat, and traits suited for an amphibious lifestyle.
The Sundarbans Tiger Reserve has seen a steady decline in its overall forest management ranking over the years, according to a 2023 report by Down To Earth. The reserve dropped from second place in 2006 to 31st among 51 tiger reserves nationwide. Interestingly, the tiger population in the Sundarbans increased from 88 in 2018 to 100 in 2022, as per the latest tiger census. However, the report highlights persistent challenges affecting the reserve’s performance—chief among them are inadequate staffing and the region’s vulnerability to climate change impacts, including rising sea levels and frequent submergence.
Meanwhile, a 2022 Mongabay report highlighted that the rapid growth of aquaculture in the Indian Sundarbans is generating significant profits for a few, while depriving local communities of their right to a sustainable future. Contrary to common belief, salinisation is not the primary factor driving this surge in aquaculture within the Sundarbans Biosphere Reserve.
The Indian Sundarbans, part of the world’s largest mangrove forest along the Bay of Bengal, comprises 102 islands—about half of which are inhabited. As rising sea levels continue to erode the coastline, both human and tiger populations are being forced into increasingly limited space, escalating the risk of conflict. Over the past two decades, the region has experienced an average sea level rise of three centimeters per year, contributing to one of the fastest rates of coastal erosion globally.