India’s Expanding Coastline: Revised Measurements and Implications

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India’s coastline has undergone significant expansion, increasing by 47.6% from 7,516 km in 1970 to 11,098 km in 2023-24. This expansion reflects advancements in measurement techniques rather than physical landmass changes. The revised coastline length offers a more precise representation of India’s coastal geography, which is crucial for maritime security, economic activities, and environmental conservation.

State-wise Changes in Coastline Length

Among Indian states, Gujarat recorded the most substantial increase, with its coastline nearly doubling from 1,214 km to 2,340 km, maintaining its position as the state with the longest coastline. West Bengal saw the highest percentage increase of 357%, growing from 157 km to 721 km. Tamil Nadu's coastline was revised to 1,068 km, surpassing Andhra Pradesh’s 1,053 km, making it the second longest coastline in India. On the other hand, Kerala experienced the smallest increase, adding only 30 km (5%) to its length. Additionally, Puducherry’s coastline shrank by 4.9 km, reflecting changes in mapping methodologies.

Revised Measurement Methodology

The increase in India’s coastline is attributed to a new scientific methodology introduced for measurement, moving away from straight-line distance calculations to a more detailed mapping approach. The National Maritime Security Coordination framework, under the Ministry of Home Affairs, developed an updated system that considers geomorphological coastal features such as bays, estuaries, inlets, and other intricate formations. This shift from earlier data, which relied on older techniques from the National Hydrographic Office and Survey of India (1970), has led to a more accurate and detailed representation of India’s coastal geography.

Significance for Policy and Planning

A precise coastline measurement has implications for maritime security, environmental conservation, disaster management, and economic planning. Coastal states rely on such data for fisheries, port development, coastal regulation, and climate adaptation strategies. The improved methodology ensures better preparedness for rising sea levels, coastal erosion, and infrastructure development, strengthening India’s approach to coastal governance.

By adopting an advanced measurement system, India enhances its maritime security framework, strengthens its strategic positioning, and ensures sustainable coastal management for the future.