India’s Coastline Revised To 11,098.8 Km In 2024: 47.6% Increase Due To Advanced Mapping

In December 2024, the Union Ministry of Home Affairs reported a significant revision in India’s coastline length.

The length of the coastline was re-assessed by the National Hydrographic Office (NHO) in coordination with the Survey of India (SoI).
The coastline increased from 7,516.6 km (1970s) to 11,098.8 km (2023-24) showing a 47.6% increase.

The Coastline Paradox

Coastlines exhibit fractal-like properties , their length increases with smaller measurement scales.
- Example: A 200-km ruler smooths over curves; a 1-km ruler captures fine estuarine details, increasing total length.
The Paradox was first identified by Lewis Fry Richardson; mathematically explained by Benoît Mandelbrot (1967).
Hypothetically, smaller units (e.g., water molecules) can give an infinitely long coastline.

The change is not due to territorial expansion or geological shifts, but due to improved measurement methodologies.
Coastline data will now be updated every 10 years, starting from 2024–25.

Coastal Boundaries: Bordered by Bay of Bengal (east), Arabian Sea (west) and Indian Ocean (south).
Coastal States and Union Territories
- States: Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Odisha, West Bengal
- Union Territories: Daman & Diu, Lakshadweep, Puducherry, Andaman & Nicobar Islands.

Coastline

Gujarat: Increased from 1,214 km to 2,340 km
- Largest absolute increase; retains longest coastline status.
West Bengal: Increased from 157 km to 721 km.
- 357% increase – highest in percentage terms.
Tamil Nadu: Increased from 906 km to 1,068 km
- Overtakes Andhra Pradesh in coastline length.

Kerala: Increased by only 30 km (5%) – the smallest increase.
Puducherry: The coastline was reduced by 4.9 km (-10.4%), due to erosion and recalibration.

Aspect	Old Methodology (1970s)	New Methodology (2023–24)
Basis of Measurement	Straight-line approximation	Inclusion of intricate coastal features
Coastal Features Measured	Basic shoreline	Estuaries, inlets, sandbars, tidal creeks
Scale Used	1:4,500,000	1:250,000
Technology Used	Manual, basic mapping tools	GIS, LIDAR-GPS, satellite altimetry, drone mapping
Accuracy	Less accurate	More precise, dynamic representation
Reported Coastline Length	7,516.6 km	11,098.8 km

Coastlines of Emergence: Occur when land is raised (uplifted) or when the sea level is lowered.
- Examples of features include bars, spits, lagoons, salt marshes, beaches, sea cliffs, and arches.
Examples in India:
- Tamil Nadu Coast (Coromandel Coast)
- Kerala Coast (Malabar Coast)
Coastlines of Submergence: Created when land is submerged due to subsidence or when the sea level rises.
Examples in India:
- India’s West Coast: Displays both emergence and submergence.
  - Northern Portion: Submerged due to faulting.
  - Kerala Coast: An emerging section of the shoreline.

Economic and Developmental Implications
- Ports & Logistics: States like Andhra Pradesh are expanding port infrastructure (e.g., Ramayapatnam, Krishnapatnam, Kakinada).
- Maritime Economy: Longer coastlines boost fishing zones, tourism, and maritime trade.
Strategic and Environmental Planning: Accurate coastline data is crucial for maritime security, infrastructure planning, and disaster preparedness.
- Maritime Security: Larger coastline requires expanded coastal surveillance and protection.
- Disaster Management:Crucial for cyclone alerts, tsunami readiness, and coastal zoning.
- Environmental Monitoring: Enhances ability to track erosion, accretion, and biodiversity patterns.

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