The Oju Hydel Project, with an installed capacity of nearly 2,200 MW, is a landmark development in India’s hydropower sector, holding both economic and strategic significance, especially for Arunachal Pradesh and the broader Northeast region. It contributes to India’s renewable energy targets, enhances energy security, and supports regional development through employment and infrastructure growth. Strategically located near the Indo-China border, it underscores the importance of border infrastructure and national security. For UPSC, APSC, and APPSC exams, the project is relevant in discussions on renewable energy, regional development, environmental management, and strategic infrastructure, making it a key example of integrated development and security in Northeast India.
About the Subansiri River
Before knowing about the Oju hydel project, let us discuss the Subansiri River. The Subansiri River originates from the Kangig Glacier range in Tibet near Mount Porom. Known as Chayul Chu in Tibet, the river flows southeast before entering India through Arunachal Pradesh. After traveling through rugged Himalayan terrain, it enters Assam at Gerukamukh and finally merges with the Brahmaputra River at Jamurighat in Lakhimpur district.
Interestingly, the Subansiri River is not just a natural waterway but also a cultural and economic lifeline, as it nurtures agriculture, fisheries, and regional ecosystems.
Subansiri River Length and Course
- Total Length: 442 km
- Length in Tibet: ~60 km
- Length in Arunachal Pradesh: ~192 km
- Length in Assam: ~190 km
- Drainage Basin: ~32,640 sq. km
The river flows through Tibet, Arunachal Pradesh, and Assam, making it a trans-Himalayan river system. After its turbulent course in the mountains, it finally spreads into the fertile plains of Assam, contributing nearly 8% of the Brahmaputra’s total flow.
Tributaries of the Subansiri River
The Subansiri River receives water from several important tributaries, both in Tibet and India. Major tributaries include:
- Tsari Chu
- Ranganadi
- Dikrong
- Kamla
- Jiyadhol
- Nye Chu
- Laro Chu
These tributaries sustain the river’s flow across varied terrains, while also supporting the ecological richness of the Brahmaputra basin.
Oju Hydel Project: Key Facts
The Oju Hydel Project is designed as a run-of-the-river scheme with daily peaking capability. It will have a 100-meter concrete gravity dam, a long headrace tunnel, and an underground powerhouse. The project is expected to generate around 8,402 million units of electricity annually.
| Particulars | Details |
| Location | Upper Subansiri District, Arunachal Pradesh |
| Installed Capacity | 2,220 MW |
| Developer | Oju Subansiri Hydro Power Corporation Pvt. Ltd. |
| Type | Run-of-the-river with daily peaking |
| Estimated Cost | ₹24,942.01 crore |
| Expected Completion | 5 years (post-clearances) |
Environmental and Social Concerns
While the Subansiri River Latest News highlights the Oju hydel Project as a landmark in hydropower, it also raises pressing environmental concerns:
- The basin lies in Seismic Zone V, the most vulnerable earthquake-prone category.
- Nearly 750 hectares of forest land will be diverted.
- Nine families face displacement, while fishing and agriculture downstream in Assam may suffer.
- Downstream communities in Lakhimpur and Dhemaji fear sudden water releases and erosion.
- Biodiversity in the Himalayan forests may be disrupted.
Other Hydropower Projects on the Subansiri River
Apart from the Oju hydel Project, several other hydropower ventures have been planned or are under construction on the Subansiri River:
- Lower Subansiri HEP (2,000 MW) – near the Assam–Arunachal border, highly contested.
- Upper Subansiri Hydropower Project
- Heo Hydropower Project (240 MW)
- Tato-I Hydropower Project (186 MW)
These projects reflect the government’s strategy to harness the immense hydropower potential of the Northeast, although local protests remain strong.
Environmental and Social Concerns
While the Oju Hydel Project has immense potential, several challenges remain.
- Cumulative impacts: With multiple dams on the Subansiri, risks of altered hydrology and ecology increase.
- Seismic risks: The project lies in seismic zone V, prone to earthquakes and landslides.
- Forest loss & biodiversity: Nearly 750 hectares of forest land will be diverted.
- Livelihood risks: Displacement, reduced fishing, and agricultural land loss could affect local communities.
- Downstream concerns: Assam’s floodplains face erosion and sudden water releases.
Conclusion
The Subansiri River continues to be at the center of debates on energy, environment, and security. The Subansiri River Latest News regarding the Oju Hydel Project reflects both India’s ambition for clean energy and the challenges of balancing ecology with development. While the project promises electricity and regional growth, it also demands rigorous safeguards to protect downstream communities, fragile ecosystems, and seismic safety. The future of the Subansiri will depend on whether India can manage this balance responsibly.
Sources
- Expert committee nod for 2,200-MW Oju hydel project near the China border
- One of India’s largest hydropower projects in China border region gets key nod
Subansiri River – FAQs
It originates from the Kangig Glacier in Tibet, near Mount Porom.
Yes, the Subansiri is considered an antecedent river as it cuts through the Himalayas.
The river is about 442 km long.
Major tributaries include Tsari Chu, Kamla, Dikrong, Ranganadi, and Jiyadhol.
The Oju Hydel Project on the river received environmental clearance in September 2025.
