Hydroelectric Projects and Environmental Movements in Sikkim

Tucked into the eastern Himalayas, Sikkim is often described as one of India’s greenest and most environmentally conscious states. It became the country’s first fully organic state and protects vast stretches of biodiversity-rich forest. Yet beneath this image of harmony lies a long and bitter struggle. The rivers that define Sikkim’s landscape, the Teesta and the Rangit, have become the site of one of the most sustained environmental movements in the country. At the heart of this conflict is a simple question: can a fragile mountain ecosystem and an indigenous way of life survive the relentless push to convert rivers into electricity?

Why Sikkim became a hydropower hotspot 🔗

Sikkim sits on enormous hydroelectric potential. Its steep gradients and fast-flowing rivers are exactly what engineers look for when planning power projects. The state government identified the Teesta and Rangit rivers as prime sites and embraced an ambitious vision of becoming a major energy exporter. This was not an isolated state decision. It was part of a national push, as the central government had launched a 50,000 MW hydroelectric initiative in 2003 to rapidly expand the country’s power capacity.

The model adopted in Sikkim is known as cascade development. Instead of one large dam, a series of dams, tunnels, and power stations are built at different stages along the same river. The idea is to extract the maximum energy from a single waterway. But this approach has a hidden cost. Because the projects are interconnected, their environmental damage also accumulates. Tunnels bored through unstable mountains, valleys flooded, and floodplains altered create what researchers call irreversible interventions on the landscape. By some accounts, the state’s dam-building drive brought it close to having one of the highest dam densities in the world.

Hydropower as “clean energy” 🔗

Hydropower is widely promoted as a clean and renewable source of energy. It produces no direct carbon emissions during operation and offers a path to meeting growing electricity demand. This is the official argument for dams on the Teesta and Rangit. The problem is that the “clean” label tends to focus only on emissions while ignoring the social and ecological disruption that large dams cause in a seismically active, ecologically sensitive region. Sikkim falls under seismic zone V, the highest earthquake-risk category, which makes the case for mega dams far more complicated than a simple emissions calculation.

The rivers and the people who depend on them 🔗

To understand the resistance, you have to understand what these rivers mean to the people living along them. The Teesta is not just a source of water or power. For the indigenous communities of Sikkim, it is sacred. The Lepchas, who consider themselves the original inhabitants of the land, and the Bhutias regard the Teesta and Rangit as integral to their cultural and spiritual heritage. Much of their folklore, songs, and traditions revolve around these rivers.

The epicentre of the conflict is Dzongu, a reserved area in North Sikkim that is the traditional homeland of the Lepchas. Dzongu lies within the buffer and transition zones of the Khangchendzonga Biosphere Reserve, an area of exceptional ecological value. This special status is not merely cultural. North Sikkim was declared a protected area by the erstwhile King of Sikkim, and indigenous rights here are constitutionally recognised through Article 371F, a provision that acknowledges the rights and interests of Sikkim’s communities after the state merged with India in 1975.

What the dams threatened 🔗

For the residents of Dzongu, the proposed dams meant displacement from ancestral land, the flooding of sacred sites, and the destruction of a landscape they had protected for generations. The fear was not abstract. The Teesta basin is home to rich and diverse flora and fauna, and the construction process itself proved damaging. Preliminary works involving blasting reportedly triggered unprecedented landslides in an already geologically fragile area. Building tunnels requires enormous quantities of explosives, deeply disturbing the mountain terrain.

The Affected Citizens of Teesta and the rise of resistance 🔗

Organised opposition crystallised in the early 2000s. After the Sikkim Power Development Corporation drew up plans for the Teesta Stage IV and Stage VI dams around 2002, the community most affected was Dzongu. In response, the Affected Citizens of Teesta (ACT) was formed. Described as a community-based, apolitical body, ACT emerged from Dzongu around 2003 and 2004 to spread awareness about the harmful effects of the dams and to build opposition.

ACT did not act alone. It drew support from the Concerned Lepchas of Sikkim (CLOS) and the Sangha of Dzongu (SOD), a monastic body. Together these groups gave the movement both grassroots energy and moral weight, anchoring it firmly in Lepcha and Bhutia identity.

The hunger strike that shook the state 🔗

The defining moment came on 20 June 2007. ACT launched what became one of the largest movements against hydropower projects in Sikkim. Two Lepcha youths, Dawa Tshering Lepcha and Tenzing Lepcha, began an indefinite relay hunger strike in the spirit of Gandhian satyagraha. They shifted the protest from the villages of Dzongu to Gangtok, where the worn-out Bhutia-Lepcha House on Tibet Road became its flagship site.

This was no brief demonstration. The relay hunger strike stretched for 915 days between 2007 and 2009, an extraordinary feat of peaceful endurance. The protesters declared they would continue until the projects planned for Dzongu were scrapped and others in North Sikkim reviewed. The movement spread beyond Sikkim’s borders, reaching Lepcha communities in West Bengal’s Darjeeling district and even New Delhi.

What the movement achieved 🔗

The sustained pressure produced real results. The government was compelled to commission a basin-level study of the carrying capacity of the river. More importantly, several dams were scrapped and others stalled. By some accounts, the defiance led to the cancellation of four hydroelectric projects in the state, a rare achievement for any people’s movement of its kind. Projects in the Lachen and Lachung areas were among those withdrawn.

Yet the people of Dzongu consider the victory incomplete. Some projects, like Teesta V, had already altered the river within Dzongu, and Teesta Stage IV continued to loom as a threat for years. The activists who led the fast, weakened by months without food, returned to their villages and turned to building sustainable farms and homestays as a living example of an alternative path.

When the warnings came true: the 2023 disaster 🔗

For years, opponents of the dams argued that building mega projects in a seismically active, glacier-fed Himalayan region was a gamble against nature. On the night of 3 and 4 October 2023, that warning materialised in catastrophic fashion.

A massive block of frozen moraine collapsed into South Lhonak Lake, a glacial lake high in North Sikkim. According to a detailed study published in the journal Science, roughly 14.7 million cubic metres of material crashed into the lake, generating a wave about 20 metres high. This breached the natural moraine dam and unleashed a glacial lake outburst flood (GLOF) that drained around 50 million cubic metres of water down the Teesta valley, eroding enormous volumes of sediment along the way.

The flood swept away the 60-metre-high dam of the 1200 MW Teesta III project at Chungthang, Sikkim’s largest hydropower project. The collapse of the dam did not absorb the flood. Instead, the sudden release of the reservoir’s water magnified the destruction downstream. Water levels rose by 15 to 20 feet in affected districts of Sikkim and West Bengal.

The human cost 🔗

The disaster killed dozens of people, with many more reported missing, and affected tens of thousands across the basin. The Government of Sikkim reported that the flood resulted in 46 lives lost, over 77 people missing, and more than 88,000 affected. Bridges collapsed, and long sections of National Highway 10, a vital artery for the state, were washed away, cutting off villages. Because the Teesta is a transboundary river, the floodwaters travelled downstream into West Bengal and on into Bangladesh.

A disaster foretold by poor governance 🔗

Critics argue this was not simply a natural calamity but the predictable outcome of flawed environmental governance. Analysts have pointed out that concerns about GLOF risk had been raised repeatedly during the clearance process for the Teesta projects over two decades, only to be brushed aside. Monitoring and early-warning systems failed on the night of the disaster, and a station that might have provided advance warning was not functioning. The collapse exposed how the impacts of cascade hydropower can ripple outward catastrophically when one link in the chain fails.

The fight continues over rebuilding 🔗

Rather than ending the dam debate, the 2023 disaster reopened it. The government and the National Hydroelectric Power Corporation have moved to rebuild Teesta III. An Expert Appraisal Committee of the environment ministry has proposed reviving the project with a taller 118-metre concrete gravity dam, claiming it can withstand the worst floods. Critics counter that fundamental questions about building a high dam in such a fragile zone remain unanswered, and that the committee itself had raised concerns about the dam’s safety and stability.

The Lepchas of the area are once again protesting, this time against reconstruction. Activists note that the environmental assessment being relied upon was prepared before 2006 and did not account for GLOF risk, the very hazard that destroyed the original dam. The new push to revive Teesta Stage IV has prompted fresh resistance, with communities fearing displacement and the loss of their homes and culture all over again, as captured in recent reporting on the Lepchas’ renewed fears.

The search for sustainable alternatives 🔗

What the Sikkim experience underscores is the need to genuinely evaluate the social and ecological costs of large dams rather than treating hydropower as automatically “green.” The movement has never been simply anti-development. ACT leaders have argued for smaller, less destructive options and have demonstrated alternatives through organic farming and community-run ecotourism. The broader call is for development models that respect indigenous self-determination, account for climate and seismic risk, and treat rivers as living systems rather than resources to be exhausted. As one prominent voice in the movement put it, the resistance is ultimately about protecting the last free-flowing stretch of the Teesta.

Why the Sikkim story matters 🔗

The conflict over the Teesta and Rangit is a microcosm of a larger tension running through development across the Himalayan region. On one side is the promise of clean energy and economic growth. On the other is the reality of ecological fragility, seismic danger, and the rights of indigenous communities whose lives are bound to the rivers. The 2023 disaster gave tragic weight to warnings that activists had voiced for years. It demonstrated that ignoring local knowledge and environmental science can carry a devastating price.

The story of ACT also shows the power of sustained, peaceful resistance. A small community in a remote corner of the country managed to halt several major projects and force the state to reconsider its plans. Whether that legacy can shape a more cautious and sustainable approach to development remains an open question, especially as rebuilding efforts gather pace.

What do you think? Should a state like Sikkim, located in the highest seismic risk zone and facing growing climate hazards, continue to pursue large hydropower projects, or do disasters like the 2023 GLOF make the case for fundamentally rethinking how development is planned in fragile mountain regions? And how much weight should the cultural and spiritual claims of indigenous communities carry when they conflict with national energy goals?

References

1. https://www.academia.edu/5123415/The_Anti_dam_Movement_in_Sikkim_Resurgence_of_Lepcha_and_Bhutia_Identity_at_Helm
2. https://sikkimproject.org/making-of-a-sacred-land-and-its-guardians/
3. http://www.actsikkim.com/
4. https://www.outlookindia.com/travel/the-paradise-worth-preserving-how-the-lepcha-community-has-built-a-resistance-against-dams-in-sikkim-news-200449
5. https://www.epw.in/engage/article/can-act-movement-sikkim-be-reactivated
6. https://www.indiawaterportal.org/articles/village-heads-come-together-save-dzongu
7. https://www.science.org/doi/10.1126/science.ads2659
8. https://iee.psu.edu/news/blog/glacier-lake-outburst-floods-loss-life-and-infrastructure
9. https://www.deccanherald.com/opinion/editorial/new-dam-old-warnings-3393904
10. https://www.aljazeera.com/features/2025/7/31/no-land-no-home-no-future-himalayan-lepchas-fear-new-dam
11. https://dialogue.earth/en/energy/locals-step-up-protests-against-large-sikkim-dam/