On December 25, China approved the construction of a mega hydropower project on the Yarlung Tsangpo river in Tibet. The dam is to be constructed at the Great Bend, just before the river enters the northeast Indian state of Arunachal Pradesh. China has said that the “measures have been taken for the security of the project and ecological environment protection” and that the dam will not have “negative impact” on downstream countries. There are concerns in India that the dam will impact water flow with serious implications for the lives and livelihoods of millions of people in the country. Should India be worried?
In an interview with The Diplomat’s South Asia editor Sudha Ramachandran, Y Nithiyanandam, one of India’s foremost experts on geospatial intelligence, and professor and head of the Geospatial Research Program at Takshashila Institution, pointed out that the dam’s location in a disaster-prone region makes the river basin vulnerable to landslides, earthquakes, and flash floods. Additionally, the dam is located in strategic territory and has geopolitical implications. “China’s reluctance to share consistent hydrological data has compounded these challenges, particularly amid recent geopolitical tensions,” he said.
What do we know so far about the mega hydropower project that China plans to build on the Yarlung Tsangpo River?
In March 2021, China’s 14th Five-Year Plan was approved, setting ambitious goals across multiple sectors, including the development of a modern energy system. Among its key initiatives is the creation of a renewable energy hub in Nyingchi prefecture, integrating hydropower, wind, and solar energy projects. The centerpiece of this strategy is the construction of a colossal 60,000 MW hydropower plant on the Yarlung Tsangpo River (Brahmaputra), boasting a generation capacity three times greater than the Three Gorges Dam, currently the world’s largest operational hydropower facility.
China’s state news agency, Xinhua, has recently confirmed the government’s financial approval for this project, described as an engineering marvel of unprecedented scale in reports. The mega-dam is planned in the lower reaches of the Yarlung Tsangpo River, close to the Line of Actual Control (LAC) between China and India — a region fraught with strategic sensitivities. This proximity has intensified concerns over potential downstream impacts, including disruptions to water flow, sediment transport, and the risks of artificial floods, which could exacerbate tensions between the two nations.
The Yarlung Tsangpo originates in the Angsi Glacier of the Tibetan Himalayas at an altitude of 5,319 meters. It flows through the Tibet Autonomous Region, carving one of the world’s deepest canyons at the “Great U Bend,” before descending into India as the Siang River and eventually transforming into the Brahmaputra in India, and the Jamuna in Bangladesh. Stretching over 3,350 kilometers and spanning four nations — China, India, Bhutan, and Bangladesh — the river and its tributaries are vital to the region, nourishing the world’s largest delta, hosting remarkable biodiversity, and supporting millions of livelihoods.
Medog county in Tibet Autonomous region, China
Source: Takshashila Geospatial Bulletin, Takshashila Institution
The proposed hydropower plant, planned near Medog County, underscores China’s ambition to dominate large-scale renewable energy development. However, it also raises serious geopolitical and ecological concerns. The scale of the project, combined with the fragility of the Himalayan ecosystem, makes the potential for environmental disruptions significant. Furthermore, the lack of transparent data-sharing mechanisms with downstream nations has heightened fears over unilateral water resource management. For India, in particular, the dam’s location near its borders is not just an environmental issue but a strategic one, adding to an already complex bilateral relationship.
While the project exemplifies China’s commitment to renewable energy, its broader implications — spanning ecological, economic, and geopolitical dimensions — warrant rigorous scrutiny and regional dialogue. Without greater transparency on the part of China and cooperative frameworks, this dam could become a flashpoint in an already delicate regional equilibrium.
What do satellite images tell us about the project’s progress?
Our analysis, published in the Takshashila Geospatial Bulletin, indicates that China is systematically reshaping the Yarlung Tsangpo region to facilitate the construction of its ambitious hydropower dam. The emergence of settlements and agricultural farms along the riverbanks strongly suggests strategic preparation for the dam’s construction and subsequent regional development. A detailed land use and land cover (LU/LC) analysis, conducted using high-resolution 10-meter Sentinel satellite imagery provided by the European Space Agency, reveals a marked transition from open land to settlements and agricultural areas within a short span of three years (2018–2021). This transformation, coupled with intensified military activity in the region, shows no signs of abating. Furthermore, China’s steady advancement toward constructing massive dams in Medog is underscored by the swift development of high-quality mountain roads, strategically located border villages, and smaller dams along the river corridor. These developments reflect a calculated effort to assert infrastructural dominance in the region.
A reservoir near the Great Bend is said to be “risky, dangerous and irresponsible.” Why?
The proposed reservoir near the Great Bend carries risks for several reasons. The dramatic elevation drop of over 2,000 meters in the Yarlung Tsangpo Canyon after the U-Bend introduces formidable engineering and environmental challenges. Questions persist regarding the project’s design and methodology, particularly whether it will utilize a reservoir-type or Run-of-River Hydropower. Such a structure could disrupt the river’s natural flow, impede the downstream transport of fertile soil, and provoke concerns about potential water diversion for China’s use — raising fears that it could serve as a geopolitical instrument under the guise of development.
Adding to these concerns, the basin’s vulnerability to natural disasters significantly magnifies the risks. Over 600 flash flood incidents have been reported in the basin since 1980, with more than 15 influencing factors identified in the river system (Fei et al., 2025). The potential for flash floods remains a serious concern due to the basin’s complex geomorphology and climatic variability. Although flash floods are less frequent in the lower reaches of the river, their occurrence cannot be discounted. The area’s seismic activity is particularly alarming, with the past year alone recording 130 earthquakes of magnitudes 4 and above. This sustained seismic activity presents a continuous threat, particularly at the proposed site, which is categorized as having high landslide susceptibility. The recent 7.1-magnitude earthquake in Shigatse Tingri caused structural deformations in nearby dams and infrastructure, further emphasizing the precariousness of the area.
This combination of engineering challenges, the basin’s susceptibility to multiple disasters — including landslides, earthquakes, and flash floods — and the geopolitical implications raises profound questions about the project’s long-term safety, viability, and regional impact.
Some Indian experts have said that since the Siang gathers most of its water due to rains in Arunachal, a reservoir or diversion of water at the Great Bend will not impact lower riparian countries.
The precipitation data available in the open domain indicates that the river stretch after the “U Bend” receives substantial rainfall just before entering Arunachal. According to a World Bank report, the Tibetan Plateau averages 734 millimeters (mm) of annual precipitation, while the Yarlung Tsangpo region sees up to 2,000 mm. Precipitation increases significantly in the eastern Himalayas, ranging from 1,000-4,000 mm, and peaks in the Brahmaputra floodplains, with 3,500-4,000 mm annually. The Jamuna floodplains in Bangladesh receive between 1,500 and 3,000 mm.
The contribution of the Yarlung Tsangpo to the Brahmaputra remains contentious due to inconsistent and often outdated data. Reliable assessments require updated ground measurements of tributaries and year-round monitoring of water flows to account for seasonal variations. Downstream countries like India face challenges in acquiring accurate data due to limited access to upstream hydrological information. While geospatial tools especially remote sensing offer valuable insights into precipitation and river runoff, they fall short in providing the level of accuracy achievable through detailed on-ground measurements.
China’s reluctance to share consistent hydrological data has compounded these challenges, particularly amid recent geopolitical tensions. The suspension of data-sharing agreements and the failure to renew critical Memorandums of Understanding highlight a troubling lack of transparency. As a result, downstream nations must rely on open-source models and datasets, which reveal anomalies in river flow patterns in the Yarlung Tsangpo basin for 2024. Data from the Australian National University’s 25-year remote sensing archive shows unprecedented highs in some areas and record lows in others, indicating potential stress on the Yarlung Tsangpo-Brahmaputra system from both climate change and upstream infrastructure development.
China’s aggressive dam-building activities, including the proposed mega-dam on the Yarlung Tsangpo, exacerbate these concerns. These projects disrupt natural river flows, complicating predictions of water availability and sediment transport for downstream nations. The cumulative impact of such projects, combined with unreliable data, threatens the ecological balance of the river basin, the livelihoods of millions, and regional stability. Without greater transparency, data-sharing, and collaborative hydrological studies, the long-term consequences for the Brahmaputra and its riparian nations remain deeply uncertain.
How will the project impact downstream regions in India and Bangladesh especially in the context of climate change?
The Yarlung Tsangpo basin encompasses over six distinct sub-climatic zones, as classified by the Köppen Climate Classification (1908–2016). While much of the basin experiences a cold, dry mountain climate, the eastern section, beyond the Great U Bend, transitions into a warm, humid tropical monsoon climate characterized by significant rainfall. These climatic variations, coupled with the effects of climate change, are likely to have profound impacts on water flow into downstream regions.
In the Tibetan Plateau, climate change is expected to alter water availability across these zones, influencing the quality, quantity, flow rate, and seasonal patterns of water reaching downstream areas in India. The tributaries of the Yarlung Tsangpo, originating from snow-covered high mountains, are primarily snow-fed. Rising temperatures and retreating glaciers threaten to disrupt the volume and flow patterns of the river, posing challenges for water availability downstream.
For India and Bangladesh, the risks are compounded by their vulnerability to extreme climate events and the impacts of anthropogenic activities along their own river basins in the Brahmaputra and Jamuna rivers. These interconnected systems face cascading risks, with downstream regions, home to dense populations and critical habitats, being particularly vulnerable. The reliance of millions on these waters underscores the urgency of addressing the potential disruptions to the fragile balance of these river systems.
Chinese analysts say that foreign media reports are amplifying the scale of the project and that it’s “impossible” to build a project of that magnitude in the area and that it would not be “cost-effective” Your views?
While the exact details of the proposed project — such as the type of technology to be employed, the engineering design, the exact site of the Dam Toe, and the mitigation measures to address potential environmental and social impacts — remain undisclosed, the announcement of its scale has naturally drawn comparisons with the world’s largest dam, the Three Gorges Dam. This comparison is primarily fueled by claims that the proposed dam’s capacity would be three times larger than that of the Three Gorges Dam, leading to significant speculation about the project’s potential size, engineering complexity, and overall impact on the region.
Although the projected capacity implies an immense structure, it is crucial to acknowledge the challenges posed by the unique terrain and environmental conditions of the proposed site. These factors could drive the development of a fundamentally different design and approach. For instance, advanced hydroelectric technologies might be required to navigate the area’s topographical constraints while minimizing disruption to the local ecosystem. Moreover, the logistical demands of constructing such a colossal project in a remote and potentially unstable environment would likely result in high costs and complex engineering challenges.
In the absence of concrete details, the discourse remains largely speculative, making it difficult to assess how the project would address critical environmental, social, and geopolitical considerations. Key concerns include the potential impact on downstream water flow, the implications for neighboring countries, and the long-term sustainability of such a massive undertaking. Until more comprehensive plans and deliberations are made public, the comparisons with the Three Gorges Dam are hypothetical at best, driven by capacity estimates and assumptions rather than substantiated facts. This lack of clarity underscores the need for greater transparency and detailed analysis before drawing definitive conclusions about the project’s feasibility and implications.
India is building multiple dams on the Siang and other rivers in Arunachal Pradesh. Would not the concerns that India is raising regarding the Medog dam apply to its own dams in Arunachal? Should Bangladesh be concerned?
The scenarios, while superficially similar, reveal fundamental differences upon closer examination. India’s dam projects are designed with a multi-pronged approach, addressing critical regional challenges such as flood mitigation, water resource management, and livelihood support. These initiatives are not driven solely by energy demands but prioritizing broader objectives like water scarcity management and climate resilience, while minimizing downstream impacts. Additionally, India has demonstrated a commitment to transparency, maintaining data-sharing mechanisms and establishing water-sharing initiatives to ensure harmony with its downstream neighbors. This approach underscores India’s role as a responsible and cooperative stakeholder in regional water management.
By contrast, the Medog dam represents a markedly different approach. The emphasis appears to be on fulfilling energy requirements, often at the expense of addressing the potential downstream consequences. Limited transparency and a lack of regional risk considerations raise significant concerns about the broader implications, especially when such large-scale projects risk disrupting entire river systems. Shifting the burden of risk onto neighboring countries without prioritizing cooperative frameworks or environmental safeguards creates a stark divergence in priorities. It highlights how the concept of responsibility can vary dramatically, shaped by differing national agendas and strategic objectives. This divergence is a crucial point for reflection, particularly in regions where shared water resources have profound geopolitical and ecological implications.