Extraction, floods and forgotten landscapes underline North Bengal’s climate debt

North Bengal stretching from the Himalayan foothills to the lush alluvial plains is inching towards an ecological collapse that can no longer be denied. The region’s long-endured wounds were laid bare once again on October 4 and 5, 2025, when catastrophic rainfall triggered floods and nearly a hundred landslides, claiming at least 28 lives and leaving many missing.

The tea industry alone has reported losses exceeding Rs 50 crore, with over 30 gardens damaged. In Jaldapara National Park, six rhinos drowned and several elephants were swept into the Jaldhaka River, according to news reports.

This is not an isolated natural disaster. It is the consequence of decades of ecological neglect, policy failure and unregulated extraction that have hollowed out North Bengal’s resilience. A region once balanced between mountain, river and plain is now buckling under human excess — its hills carved up, its rivers mined, and its forests erased in the name of progress.

Mining rivers to death

Across Darjeeling, Jalpaiguri, Cooch Behar and Alipurduar, the rivers that define North Bengal’s landscape are being mined to death. Illegal quarrying of sand and stone has exploded in recent years, with more than 500 quarries gouging riverbeds — most of them operating without licences or oversight, according to a 2020 report by the South Asia Network on Dams, Rivers and People.

In the Mahananda River alone, locals estimate that 250-300 truckloads of sand are hauled out daily from the Fulbari-1 Ghat. The Balasun, Rakti, Mechi, and Chenga  rivers suffer the same fate — plundered, often at night, with the quiet complicity of officials. This is no petty law-breaking; it is organised looting, driven by a construction economy that prizes concrete over conservation.

A recent study by the Department of Geology, University of North Bengal found that the Balasun River, a sub-Himalayan tributary of the Mahananda, loses an astonishing 6.84 million cubic metres of riverbed material each year. This rate surpasses extraction levels recorded in European, American or Japanese rivers.

As a result, the upper streams can no longer move sediment naturally, while the heavily mined lower reaches have widened, weakened and lost flow energy. Finer sediments that are vital for maintaining the river’s natural equilibrium are disappearing, leaving the banks brittle and prone to collapse. When flash floods tore through the Balasun on October 5, they destroyed the Dudhiya Bridge and swept away homes along its banks.

In the eastern Dooars, the Raidak basin tells a similar story. Nearly 27 per cent of its 285-square-kilometre catchment is now among the most flood-prone zones, thanks to deforestation, unplanned embankments and the destruction of natural wetlands. A study of the Raidak-II River recorded 28 sand and gravel mining sites along a 35-kilometre stretch. Years of heavy machine-driven extraction have thrown the river off balance — its channels widened, banks shifted, and the bed rising and sinking unpredictably, showed another paper.

Neighbouring rivers such as the Teesta, Jaldhaka, Torsha and Kaljani have also changed course repeatedly, submerging villages that once stood safe for generations. After the 2023 flash flood, the Teesta’s riverbed rose by as much as 12 metres in places, choking its flow. When the monsoon arrives now, these already plundered rivers burst through their confines with brutal force, inundating homes, schools and farmlands.

When ‘development’ devours itself

Urbanisation in North Bengal is a continuation of a colonial legacy that began between 1871 and 1922, when railway lines, embankments and dams were built across fragile terrain with little regard for ecology. The legacy persists; only now, the pace is faster and the slopes more unstable.

Studies show that construction on fragile hillsides, often without any geotechnical planning, is accelerating soil erosion and landslides. Roads, hotels and multi-storeyed buildings are now carved into mountainsides once held firm by dense forests.

A recent remote-sensing assessment found that the eco-environmental quality of Darjeeling and Kalimpong has deteriorated from “moderate” to “degraded” over the past decade. “Darjeeling lies in a high seismic area and is naturally prone to landslides,” said professor Shailendra Mani Pradhan, a disaster management expert at Sarojini Naidu College for Women. “Yet infrastructure development for tourism and housing continues without adherence to building bylaws or drainage norms. The terrain is being pushed to its limits.”

Around 70-80 per cent of land within Darjeeling Municipality has been allotted for residential use, which Pradhan called “unsustainable”.

At the foothills, the city of Siliguri has become an emblem of unplanned expansion. Farmlands and bamboo groves are vanishing at an annual rate of 4-6 per cent, replaced by concrete. Between 2001 and 2015, Siliguri’s built-up area more than doubled, from 17 to nearly 37 square kilometres, a 114 per cent rise, while natural vegetation declined by 23 per cent.

Researchers estimate this loss has cost the region about $9 million per hectare in ecosystem services over 15 years. If the trend continues, a further 20 per cent loss in ecological value could occur within decades. Siliguri’s sprawl mirrors that of many Indian cities — mid-sized, under-regulated, and sitting on the fault line between growth and ecological collapse.

Peaks in peril

The 2023 Teesta River disaster exposed the fragility of the eastern Himalayas. Climate change and intense rainfall triggered a glacial lake outburst flood (GLOF) from South Lhonak Lake in Sikkim, which obliterated the 1,200-MW Teesta-III dam at Chungthang and killed more than 40 people.

Scientists had long warned of the lake’s instability, but the dam was built regardless in a seismic and glacially active zone. The floods tore through the Teesta valley, destroying bridges, homes and hydropower projects once touted as symbols of “green energy”.

Roughly 270 million cubic metres of sediment were unleashed, altering the flow of the Teesta, Jaldhaka, Torsha and Kaljani rivers. Villages such as Krishnagram and Ghafoor Basti in Teesta Bazar have since endured repeated inundation, forcing families to abandon their homes. In Jalpaiguri, settlements like Laltong and Chamakdangi were left in ruins, displacing about 200 families.

This year, the flooding worsened as heavy rain in Bhutan and a malfunction at the Tala Dam overwhelmed rivers in Jalpaiguri and Alipurduar. Floating logs from Bhutan’s timber depots blocked the Torsa’s course, magnifying the destruction across the Dooars.

Warming, unstable frontier

Climate change is the accelerant behind this chain of disasters. A Nature report warns that if global temperatures rise by 1.5°C or more, nearly two-thirds of Asia’s high mountain glaciers could vanish by century’s end. Bhutan alone has over 2,500 glacial lakes, 31 of them classified as “very high hazard”. As these expand and rainfall intensifies, the risk of catastrophic floods across the eastern Himalayas will only grow.

North Bengal is already feeling that heat. More than 100 landslides, including 35 major ones, were recorded during the October deluge. A study using data from 1970-2018 predicts a 23 per cent surge in extreme precipitation events in the Teesta basin by the mid-21st century. In a region with steep slopes, fragile geology and active fault lines, that could mean a near-annual cycle of disaster.

Despite these warnings, large-scale infrastructure projects continue unabated. Roads and railway lines have been gouged into mountainsides, often without proper slope stabilisation. The 45-kilometre Sivok-Rangpo Railway Project, which links West Bengal to Sikkim, cuts through 14 tunnels, crosses 22 bridges, and passes five stations — including Teesta Bazar, already prone to flooding.

Environmentalists have questioned the project’s safety and ecological costs. The eastern Himalayas have “moved from a ‘climate change’ to a ‘climate crisis’ stage,” environmental expert Satyadeep Chhetri after the October floods said in an interview to news agency PTI. He urged the government to relocate habitations from high-risk zones and rehabilitate affected families, warning that “large-scale hill-cutting for highways and the railway line to Rangpo has destabilised the terrain.”

The politics of spectacle

North Bengal’s crisis is as political as it is ecological. The region has long been treated as a periphery — useful for its tea, timber and tourism, but rarely central to the state’s planning priorities. The disconnect was stark this year, as festive lights from Durga Puja carnivals in Kolkata flashed across television screens while hill communities mourned their dead.

Public anger is growing. Locals accuse successive governments of turning disasters into photo-opportunities while ignoring the structural causes — unregulated mining, deforestation and reckless construction. “Development”, many point out, has become an empty slogan when it leaves people poorer, rivers shallower and hills more unstable.

The crux of the crisis is both ecological and political ignorance. Ravaged riverbeds, vulnerable terrains, and weakened ecosystems intensify every monsoon fury—these are all predictable outcomes of a years-old extractive development model that treats nature as disposable. 

In this current situation relief must reach people before rhetoric, sustainable development must replace short-term optics, and governance has to become participatory and above disruptive politics. Climate-resilient infrastructure, disaster management strategies, local empowerment with accountability, reforestation, and river basin management are the need of the hour for safety, equity, and ecological stability of this region. 

North Bengal is an ecologically and strategically sensitive terrain. Electoral theatrics and nonchalant attitudes from both the center and the state have made North Bengal pay the price for ecological neglect; a cost this region can no longer afford.

Jayanwita Sarkar is assistant professor, department of botany, Cooch Behar Panchanan Barma University

Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth