Climate Change and Indus Waters Treaty: IIT Gandhinagar Study on Eastern Rivers

Subject GS Paper 3: Environment

Context: A first-of-its-kind study by IIT Gandhinagar has found that precipitation in the catchments of the eastern rivers (Ravi, Beas, and Sutlej) declined by nearly 20% between 1951 and 2024, providing scientific evidence that climate change has significantly altered water availability in the Indus River Basin. 

• The findings strengthen India’s case for revisiting the Indus Waters Treaty (IWT), 1960.

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Key Findings of the Study

• Declining Rainfall in Eastern Rivers
  • 20% decline in precipitation in the Ravi, Beas, and Sutlej catchments (1951–2024).
  • These rivers are allocated exclusively to India under the Indus Waters Treaty.
• Stable Rainfall in Western Rivers
  • Indus, Jhelum, and Chenab recorded only a 6% decline, which is statistically insignificant.
  • Water availability in Pakistan’s allocated rivers has remained relatively stable.
• Groundwater Depletion
  • Significant depletion of groundwater observed in the Ravi and Sutlej sub-basins.
  • Western river basins showed relatively healthier groundwater due to:
    • Lower agricultural pressure.
    • Lower population density.
    • Greater recharge from snowfall and precipitation.
• Declining Reservoir Inflows
  • Major Indian reservoirs witnessed a substantial fall in annual inflows:
    • Pong Dam: Nearly 34% decline (1951–2020).
    • Bhakra and Thein reservoirs also recorded declining inflows.
  • In contrast, Pakistan’s Mangla and Tarbela reservoirs showed only marginal declines.

Why is Study Important?

• Provides the first scientific, data-based evidence that climate change has altered hydrological conditions in the Indus Basin.
• Supports India’s argument that the hydrological assumptions underlying the Indus Waters Treaty (1960) have fundamentally changed.
• Highlights that water availability is no longer consistent with the conditions prevailing when the treaty was signed.

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India’s Position on the Indus Waters Treaty

India has argued that the Treaty requires review and modification because of:

• Climate change altering river flows.
• Population growth increases water demand.
• Need for clean energy expansion (hydropower).
• Changing developmental requirements.
• Increased variability in rainfall and water availability.

Following the Pahalgam terrorist attack (2025), India declared the Treaty to be “in abeyance”, while reiterating that it would remain so until Pakistan credibly and irrevocably ends support for cross-border terrorism.

Implications for India

• Water Security: Reduced water availability in eastern rivers could affect:
  • Irrigation.
  • Drinking water supply.
  • Agricultural productivity.
• Hydropower: Lower reservoir inflows may reduce hydropower generation in northern India.
• Climate Adaptation: Highlights the need for climate-resilient river basin management and improved groundwater governance.
• Transboundary Water Governance: Demonstrates that water-sharing agreements should incorporate climate variability and adaptive management.

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Indus River System

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