1. In December 2024, the Union Ministry of Home Affairs announced that India’s coastline length increased from 7,516.6 km to 11,098.8 km.

2. The National Hydrographic Office (NHO), together with the Survey of India (SoI), checked the coastline again.
3. This shows a 47.6% increase compared to the old measurement from the 1970s.
4. This change was not because India gained new land or islands.
5. It happened because of better ways to measure the coastline.

Why Did the Coastline Length Change?

1. The old measurement used maps that were not very detailed and had a scale of 1:4,500,000.
2. This missed many small features like estuaries, creeks, and sandbars.
3. Islands like Andaman & Nicobar and Lakshadweep were not fully counted before.
4. The new measurement used more detailed maps at a scale of 1:250,000.
5. Modern technology like GIS, satellite data, LIDAR-GPS, and drones helped in measuring.
6. The measurement was done using the high tide line as a base.
7. River mouths and creeks were measured by drawing boundaries inland to keep things consistent.
8. Islands that appear at low tide were also included.
9. This gave a longer coastline length.
10. The government will update coastline length every 10 years from 2024-25 onwards.

How GIS, Satellite Data, LIDAR-GPS, and Drones Helped Measure the Coastline

 

1. GIS (Geographic Information Systems) helps collect, store, and analyze geographic data on maps.
   1. It allows combining many types of data like satellite images, surveys, and maps into one system.
   2. This helps map the coastline in much greater detail than before.
   3. Satellite data provides high-resolution images of large coastal areas from space.
   4. Satellites can capture details about the shoreline, landforms, and changes over time.
   5. This helps measure the coastline more precisely and monitor erosion or land changes regularly.
2. LIDAR-GPS uses laser light from aircraft or drones to measure distances very accurately.
   1. It creates detailed 3D maps of the land and coastline by scanning its shape and height.
   2. GPS helps pinpoint exact locations, making measurements very precise.
   3. This method can capture small features like sandbars, tidal flats, and creeks that older maps missed.
3. Drones can fly close to the coastline and take detailed photos and videos from many angles.
   1. They can cover areas that are hard to reach or too small for satellites to see clearly.
   2. Drones provide up-to-date images that help update coastline maps quickly.
   3. Together, these technologies provide a clearer, more accurate, and detailed picture of India’s coastline.
   4. This is why the new coastline length is much longer than earlier estimates.

The Coastline Paradox Explained

1. The coastline paradox means the length of a coastline depends on how closely you measure it.
2. Coastlines have many small bends and details that become clear when you measure carefully.
3. Using a large ruler smooths out many details and shows a shorter length.
4. Using a small ruler shows more details and makes the coastline seem longer.
5. Lewis Fry Richardson first noticed this in the 1950s.
6. Benoît Mandelbrot explained it in 1967 using math.
7. He showed how the measured length of Britain’s coast changed with the ruler size.
8. If you measure with very tiny units, the length could become almost infinite.
9. So, the longer coastline of India is because of better and more detailed measurements, not actual land changes.

Geographical Coverage of India’s Coastline

1. India’s coastline touches the Bay of Bengal in the east, the Arabian Sea in the west, and the Indian Ocean in the south.
2. There are 11 coastal states including Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Odisha, and West Bengal.
3. Coastal Union Territories include Daman & Diu, Lakshadweep, Puducherry, and Andaman & Nicobar Islands.
4. Some states showed big increases in coastline length:
   1. Gujarat’s coastline grew from 1,214 km to 2,340 km, still the longest.
   2. West Bengal’s coastline grew from 157 km to 721 km, the largest percentage increase (357%).
   3. Tamil Nadu’s coastline grew from 906 km to 1,068 km, overtaking Andhra Pradesh.
5. Some states had little or no increase:
   1. Kerala’s coastline increased by only 30 km (5%).
   2. Puducherry’s coastline reduced by 4.9 km (-10.4%) because of erosion and better measuring.

Old vs New Measurement Methods

Aspect	Old Method (1970s)	New Method (2023-24)
Measurement basis	Straight lines	Includes all coastal features
Coastal features counted	Basic shoreline	Estuaries, creeks, sandbars, inlets
Map scale	1:4,500,000	1:250,000
Technology	Manual mapping	GIS, satellite, LIDAR-GPS, drones
Accuracy	Less accurate	More accurate and detailed
Coastline length	7,516.6 km	11,098.8 km

Types of Coastlines: Emergence and Submergence

1. Coastlines of emergence happen when land rises or sea level falls.
2. Features include beaches, lagoons, salt marshes, cliffs, and sea arches.
3. Examples are the Tamil Nadu coast (Coromandel Coast) and Kerala coast (Malabar Coast).
4. Coastlines of submergence happen when land sinks or sea level rises.
5. India’s west coast shows both types:
   • Northern parts are submerged due to faulting.
   • Kerala coast is mostly an emerging shoreline.

Economic and Development Effects

1. The longer coastline helps in developing ports and shipping facilities.
2. Andhra Pradesh is building more ports like Ramayapatnam, Krishnapatnam, and Kakinada.
3. A longer coastline means more fishing areas, better tourism, and more trade.
4. Accurate coastline data helps plan security and disaster management.
5. It is important for coastal protection and disaster warnings like cyclones and tsunamis.
6. It also helps monitor environmental changes like erosion and the health of coastal plants and animals.