India’s Major River Deltas Sinking at Alarming Rates: Nature Study

A recent research published in the journal Nature has warned that several of India’s major river deltas are sinking rapidly, increasing the risk of flooding for millions of people due to excessive groundwater extraction and rising sea levels.

About the Study

• The analysis examined 40 major river deltas across 29 countries on five continents.
• These deltas are home to over 236 million people, many of whom face heightened flood risks in the near future.

Indian River Deltas Identified

The study highlights significant land subsidence in the following Indian deltas:

• Ganga–Brahmaputra Delta
• Brahmani Delta
• Mahanadi Delta
• Godavari Delta
• Cauvery Delta
• Kabani Delta

This places millions of people living in these regions at growing risk of coastal and river flooding.

Key Cause: Human Activity

• Human activity was identified as the dominant driver of land subsidence.
• Excessive groundwater extraction emerged as the primary factor accelerating land sinking in river deltas worldwide.

Global Importance of River Deltas

• River deltas occupy only about 1% of the world’s land area.
• Yet, they support 350–500 million people, nearly 6% of the global population.
• They host 10 of the world’s 34 megacities, making them socio-economically critical regions.

Why Deltas Are Highly Vulnerable

• Deltas are low-lying landforms, with large areas less than two metres above sea level.
• They are extremely vulnerable to:
  • Sea-level rise
  • Storm surges
  • Land subsidence
  • Changing rainfall and temperature patterns
  • Other climate-driven pressures

Impacts of Combined Threats

The study warns that these pressures:

• Damage farmland
• Disrupt freshwater supplies
• Increase saltwater intrusion
• Accelerate wetland loss
• Worsen coastal and river flooding
• Put critical infrastructure at risk

Source: https://www.nature.com/articles/s41586-025-09928-6