On July 19, 2025, reports surfaced that China had commenced construction of a colossal hydropower dam on the Yarlung Tsangpo (referred to as the Brahmaputra in India), in Medog County of Tibet—just about 50 km from the de facto border with the Indian state of Arunachal Pradesh.
With a proposed capacity of 60,000 MW, the project is set to surpass even China’s Three Gorges Dam in scale, featuring deep tunnelling through the seismically active Great Bend region of the eastern Himalayas.
Alarm bells have sounded across India and Bangladesh, with regional leaders warning of downstream environmental risks, potential flood disasters, and strategic leverage—a phenomenon encapsulated in the indelible phrase: “ticking water bomb.” The dam’s proximity to Arunachal Pradesh—territory claimed by Beijing as “South Tibet”—adds layers of complexity to already tense boundary disputes.
Project Overview: What We Know (and Don’t Know)
Planned Capacity & Cost
Capacity: ~60,000 MW—more than three times the capacity of the Three Gorges Dam.
Estimated Cost: Approximately USD 137 billion, per available estimates.
The dam—often referred to in Indian commentary as the “Great Bend Dam” or “Medog Dam”—lies close to Arunachal’s border near Namcha Barwa and the U‑turn in the river.
Site & Timeline
Location: Medog County, Nyingtri Prefecture, Tibet—just outside the Indian state of Arunachal Pradesh.
Terrain: Gorge is narrow, steep, and seismically active—a critical concern for earth‑quake resilience and landslide risk.
Timeline: Chinese approval came in late 2024. Works began mid‑2025. Official completion dates are not public; estimates suggest multi‑year implementation given scale and underground tunnelling demands.
Opacity Around Details
Transparency: Virtually no publicly available environmental impact assessment, displacement figures, or hydrological modelling from China.
International Water Treaties: China is not a party to the UN Convention on Transboundary Watercourses (1997) and has no existing water-sharing treaty with India or Bangladesh.
Indian Political & Strategic Reactions
Arunachal Pradesh Chief Minister
Pema Khandu has consistently warned of severe consequences, dubbing the dam a “ticking water bomb.” He underscored existential threats to Adi tribal communities, local livelihoods, farmland, and properties if China were to release water abruptly or restrict flow downstream.
Khandu reiterated that the dam poses a bigger threat than even a military conflict—because the river is life. He emphasized the lack of legal safeguards, as China has not signed international water conventions.
State & National Leadership Sentiments
Former MP Ninong Ering (Pasighat West, Arunachal) called on the state government to escalate the issue with the Centre, calling for a formal water treaty with China to protect downstream regions of India and Bangladesh.
The Ministry of External Affairs publicly confirmed that India formally lodged objections with China on December 30, 2024, insisting on transparency, data sharing, and risk mitigation through existing diplomatic channels including the Expert-Level Mechanism established in 2006.
Environmental and Hydrological Risks
Seismic Vulnerabilities
The dam site lies in a high seismic hazard zone—on a major tectonic fault. Experts have warned that reservoir-induced seismicity, landslides, mud-rock flows and glacial lake outbursts could all threaten both dam integrity and downstream safety.
Ecological Impacts
Biodiversity: The region is ecologically diverse, rich in endemic flora/fauna. Large-scale habitat disruption and alteration of riverine ecology may result.
Sediment Flow: China’s dam could alter sediment transport, affecting downstream fertility and river morphology across Assam and Bangladesh.
Waterflow Uncertainties
While China insists the dam is a run-of-the-river design with minimal flow disturbance, there is widespread skepticism over whether substantial reservoir storage will exist—enough to permit seasonal water manipulation or sudden discharge.
Real-time river‑flow data is not shared. India lacks assurances about operations during monsoon, lean-season, or emergency scenarios.
Regional Water Security Implications
For India (Arunachal, Assam, Beyond)
Flood risk: Sudden discharge—intentional or accidental—could unleash flash floods in Siang, western Arunachal, and northern Assam.
Water scarcity: Reduced winter or lean-season flow can undermine irrigation, fisheries, and drinking water availability.
Hydropower disruption: Indian projects like Lower Subansiri (2,000 MW), Dibang (3,000 MW), Kameng, and others could be adversely impacted by changed flow regimes.
For Bangladesh
Bangladesh, farthest downstream, is vulnerable to both flood surges and lower dry-season flows—threatening agriculture, fisheries, deltaic ecosystems, and economic security.
Geopolitical & Strategic Dimensions
Power Asymmetry & Leverage
As upper riparian, China holds sovereign capacity to unilaterally alter flows—or withhold them—without prior consultation. India’s repeated diplomatic appeals lack enforceability absent a binding agreement.
Water as a Weapon?
While many experts argue China has no intent to weaponize water, the strategic ambiguity and lack of transparency raise concerns. Khandu emphasized the possibility—especially during times of border escalation—of using sudden water release as a coercive tool.
Broader Bilateral Tensions
The dam project exists in a larger tapestry of Sino–Indian friction: territorial claims, tensions over Arunachal Pradesh, the 2020 Galwan clashes, and growing competition over Himalayan infrastructure and river control.
Indian Strategic Responses & Contingency Planning
Siang Upper Multipurpose Project
In response, the Arunachal Pradesh government and Centre have proposed the Siang Upper Multipurpose Project—a large dam (initially pitched at ~10,000 MW) upstream in Arunachal to store water, buffer floods, and ensure water availability even during disrupted Yarlung Tsangpo flows.
Engagement plans with local tribal communities (e.g. the Adi tribe) are reportedly underway to ensure inclusion and mitigate displacement.
Diplomacy & Mechanisms
India continues using diplomatic channels—including the Expert‑Level Mechanism with China established in 2006—to press for:
Real-time hydrological data sharing.
Formal institutional oversight.
Environmental impact assessments.
Binding legal frameworks (though China is not a signatory).
Nevertheless, India lacks a treaty of the kind Pakistan has under the Indus Waters Treaty—a point of contention among policy experts.
Expert Perspectives: From Alarm to Nuance
Alarmist Views
Experts in Indian strategic circles warn that the dam’s construction—without transparency—represents a potential existential threat to riverine life, regional ecology and water security.
Political leaders stress China’s unpredictability and the possibility of “weaponizing” water during conflicts.
More Moderate Voices
Some analysts point out that only a fraction (estimated 7–30 %) of Brahmaputra water originates in Tibet; most comes from Indian tributaries and monsoon rainfall.
NR Ghosh (Observer Research Foundation) notes China's dams are primarily run-of-the-river—and while impacts are possible, China lacks capacity to “turn off” the Brahmaputra completely.
Still, even limited capacity to regulate downstream flow—especially during low-water months—can affect agriculture and hydroelectric generation across Northeast India and Bangladesh.
Environmental & Social Costs: Lessons from Three Gorges and More
Precedents of Displacement
China’s Three Gorges Dam displaced roughly 1.3 to 1.5 million people, disrupted ecosystems and submerged cultural heritage; Medog may echo some of these costs albeit on a smaller, but still significant scale.
Tibetan rights groups warn Medog’s construction may threaten sacred Buddhist sites and local communities in culturally sensitive zones.
Ecological Fragility
Similar to earlier dams on Mekong and other tributaries, the dam may alter sedimentation, reduce biodiversity, and increase riverbank erosion downstream.
Broader Implications: Transboundary Water Security in Asia
The dam is emblematic of a larger global competition over transboundary river governance. As China pursues renewable energy goals and hydropower expansion, downstream nations face strategic vulnerabilities—especially where no treaties exist.
The Brahmaputra’s future underscores the necessity for comprehensive water-sharing treaties, real-time data sharing, and joint environmental assessments, as advocated by legal experts like Mohan V. Katarki.
The geopolitical backdrop includes not just India–China relations, but also the welfare of Bangladesh, which is most downstream and most vulnerable.
Conclusion: Perils, Preparedness, and Policy Imperatives
China’s mega-dam on the Yarlung Tsangpo/Brahmaputra near Arunachal Pradesh poses multi-dimensional challenges:
Geopolitics: Redefines power asymmetry; upstream riparian control without treaties.
Environment: Risk of seismic-induced disasters, environmental degradation, and biodiversity loss.
Water Security: Risk of unilateral flow control affecting agriculture, hydropower, and livelihoods.
Regional Stability: Threatens India–China engagement, especially given Arunachal’s disputed status.
India’s countermeasures—including diplomacy, proposed large-scale dams on the Siang, and public warnings—are necessary steps, but likely insufficient without binding legal frameworks and transparent data-sharing mechanisms.
In the absence of trust or treaty obligations from China, downstream nations need to:
1. Solidify regional cooperation (India–Bangladesh).
2. Push for multilateral hydrological monitoring regimes.
3. Consider legal recourse under customary international law to prevent “significant harm.”
4. Strengthen local resilience through strategic infra (e.g., Siang dam) and community preparedness.
Final Reflection
This dam symbolizes the challenges of transboundary water governance in a rapidly changing geopolitical and environmental landscape. It brings into focus the tension between one nation’s energy ambitions and downstream nations’ rights, safety, and ecosystems.
India, Bangladesh, and international stakeholders now face a pressing responsibility:
To advocate for transparency, data-sharing and multi-lateral water governance.
To protect the river lifeline that sustains millions downstream.
To navigate the tension where hydropower intersects with national security, sovereignty, and ecological stewardship.
Only through robust diplomacy, legal frameworks, and preparedness can downstream nations hope to manage the risks posed by this unprecedented infrastructural feat.