Why in the News?

The Tamil Nadu government, with World Bank support, has launched a ₹50 crore restoration project for the sinking Kariyachalli Island.

About Kariyachalli Island:

Overview: Kariyachalli Island is one of the 21 uninhabited islands in the Gulf of Mannar Marine National Park.
Geographic Location: It lies 4 km south of Sippikulam and 20 km northeast of Thoothukudi, between Rameswaram and Thoothukudi.
Made of Reef Sediments: The island is a low-lying landform made of reef debris, sand dunes, spits, and sandy plains.
Biodiversity Hotspot: Located in India’s coral reef zone, it supports 4,300+ marine species, including 132 coral types and the endangered dugong.
Ecological Importance: It has seagrass beds and coral reefs that provide food and shelter for marine life.
Natural Coastal Shield: Kariyachalli acts as a barrier against cyclones and tsunamis, helping protect the Tamil Nadu coast.
Historical Significance: It played a role in mitigating the 2004 Indian Ocean tsunami impact.

Rapid Land Loss: The island has shrunk by over 70%, from 20.85 ha in 1969 to under 6 ha in 2024.
High Tide Erosion: At high tide, only 3.14 ha remains, per an IIT Madras (2025) study.
Wave and Sediment Pressure: Wave action, sediment loss, and lack of natural shoreline defense are accelerating erosion.
Climate Change Impact: Rising sea levels and coral bleaching have weakened the island’s natural protection.
Seagrass Depletion: Loss of seagrass beds has reduced the island’s ability to hold sediments and resist erosion.
Extreme Weather Events: Frequent cyclones and storms are making the island more vulnerable.
Future Risk: If the current trend continues, Kariyachalli may vanish by 2036.

[UPSC 2023] Which one of the following is the best example of repeated falls in sea level, giving rise to present-day extensive marshland?

Options: (a) Bhitarkanika Mangroves (b) Marakkanam Salt Pans (c) Naupada Swamp (d) Rann of Kutch*