India’s Coastline Revised to 11,098.8 km in 2024: 47.6% Increase Due to Advanced Mapping

26 May 2025

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.

Geographical Coverage of India’s Coastline

  • 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.

States/UTs with Significant Growth

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.

States/UTs with Minimal or Negative Growth

  • 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

Impacts of Coastline Expansion

Coastlines of Emergence and Submergence

  • 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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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
Integration of PYQ within the booklet
Designed as per recent trends of Prelims questions
हिंदी में भी उपलब्ध

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