• The Indian coastline is 7516.6 km long and covers 6100 km of mainland coastline.
• The straight and regular coastline of India is the result of the faulting of the Gondwana land during the Cretaceous period.
• The coastline of India touches 13 states and Union Territories.
• The western coastal plains are along the Arabian Sea.
• The eastern coastal plains are located along the Bay of Bengal.
• India is surrounded by sea on three of its sides.
• The coastal plains in India are along the west and east of the country.
• The coastal plains in India are of two types: Western Coastal Plains and Eastern Coastal Plains.

West Coast of India

• The west coast strip extends from the Gulf of Cambay in the north to Cape Comorin in the south.
• It is divided into three regions: Konkan coast, Karnataka coast, and Kerala coast.
• Alluvium from Western Ghats forms the strip.
• It contains coves, creeks, and a few estuaries.
• The Narmada and Tapi estuaries are major ones.
• The Kerala coast has lakes, lagoons, and backwaters.
• The largest lake is Vembanad Lake.

Western Coastal Plains of India:

• The western coast of India stretches from Rann of Kachchh in the north to Kanniyakumari in the south.
• It is divided into four regions: Kachchh and Kathiawar coast, Konkan coast, Karnataka coast, and Malabar coast.
• Kutch and Kathiawar region:
  • Kutch and Kathiawar are an extension of Peninsular plateau.
  • Kathiawar is made of the Deccan Lava, and there are tertiary rocks in the Kutch area.
  • They are still treated as an integral part of the Western Coastal Plains because they are now leveled down.
  • Kutch Peninsula used to be an island surrounded by seas and lagoons.
  • The Indus River used to flow through this area, filling the seas and lagoons with sediment.
  • The lack of rain has turned the area into an arid and semi-arid landscape.
  • The Great Rann is a salt-soaked plain to the north of Kutch, and the Little Rann lies on the coast and south-east of Kachchh.
  • Kathiawar Peninsula lies to the south of the Kachchh.
  • The central part of Kathiawar is a highland of Mandav Hills from which small streams radiate in all directions.
  • Mt. Girnar (1,117 m) is the highest point of Kathiawar and is of volcanic origin.
  • The Gir Range is located in the southern part of the Kathiawar peninsula.
  • The Gir Range is covered with dense forests and is famous as the home of the Gir lion.
  • 
• Gujarat Plain:
  • The Gujarat Plain lies east of Kachchh and Kathiawar and slopes towards the west and south-west.
  • The plain is formed by the rivers Narmada, Tapi, Mahi, and Sabarmati.
  • It includes the southern part of Gujarat and the coastal areas of the Gulf of Khambhat.
  • The eastern part of the plain is fertile enough to support agriculture.
  • The greater part of the plain near the coast is covered by windblown loess, which are heaps of sand.
• Konkan Plain:
  • The Konkan Plain is south of the Gujarat plain.
  • It extends from Daman to Goa and is 50 to 80 km wide.
  • The plain has some features of marine erosion, including cliffs, shoals, reefs, and islands in the Arabian Sea.
  • The Thane creek around Mumbai is an important embayment.
  • An embayment is a recess in a coastline forming a bay.
  • The Thane creek provides an excellent natural harbor.
• Karnataka Coastal Plain:
  • The plain extends from Goa to Mangalore.
  • It is a narrow plain with an average width of 30-50 km, and the maximum width is 70 km near Mangalore.
  • At some places, the streams originating in the Western Ghats descend along steep slopes and make waterfalls.
  • The Sharavati waterfall is an impressive waterfall known as Gersoppa (Jog) Falls, which is 271 m high.
  • Angel falls (979 m) in Venezuela is the highest waterfall on earth.
  • Tugela Falls (948 m) in Drakensberg mountains in South Africa is the second-highest waterfall.
  • Marine topography is quite marked on the coast.
• Malabar Plain (Kerala Plain:
  • The Kerala Plain is also known as the Malabar Plain.
  • It is located between Mangalore and Kanniyakumari.
  • The plain is much wider than the Karnataka plain.
  • It is a low-lying plain.
  • The existence of lakes, lagoons, backwaters, spits, etc. is a significant characteristic of the Kerala coast.
  • The backwaters, locally known as kayals, are the shallow lagoons or inlets of the sea lying parallel to the coastline.
  • The largest among these is the Vembanad Lake, which is about 75 km long and 5-10 km wide.
  • The Vembanad Lake gives rise to a 55 km long spit.

East Coast of India

• Lies between the Eastern Ghats and the Bay of Bengal.
• It extends from the Ganga delta to Kanniyakumari.
• It is marked by deltas of rivers like the Mahanadi, the Godavari, the Krishna, and the Cauvery.
• Chilka lake and the Pulicat lake (lagoon) are the important geographical features of the east coast.

Eastern Coastal Plains of India:

• The plains extend from the Subarnarekha river along the West Bengal-Odisha border to Kanniyakumari.
• A major part of the plains is formed as a result of the alluvial fillings of the littoral zone by the rivers Mahanadi, Godavari, Krishna, and Cauvery, comprising some of the largest deltas.
• These plains are extensive with an average width of 120 km.
• The plain is known as the Northern Circars between the Mahanadi and the Krishna rivers and Carnatic between the Krishna and the Cauvery rivers.
• The Eastern coast is divided into three categories: Utkal coast, Andhra coast, and Coromandel coast.
• 
• Utkal Plain:
  • The Utkal Plain comprises coastal areas of Odisha.
  • It includes the Mahanadi delta.
  • The most prominent physiographic feature of this plain is the Chilka Lake.
  • Chilka Lake is the biggest lake in the country and its area varies between 780 sq km in winter to 1,144 sq km in the monsoon months.
  • South of Chilka Lake, low hills dot the plain.
• Andhra Plain:
  • Extends from Utkal Plain to Pulicat Lake
  • Delta formation by rivers Godavari and Krishna is a significant feature
  • Two deltas have merged to form a single physiographic unit
  • Combined delta has advanced by about 35 km towards the sea in recent years
  • Kolleru Lake was once a lagoon at the shore, but now lies far inland
  • Straight coast and lacks good harbours with the exception of Vishakhapatnam and Machilipatnam.
• Tamil Nadu Plain:
  • The Tamil Nadu Plain is a stretch of land that runs for 675 km along the coast of Tamil Nadu, from Pulicat Lake to Kanniyakumari.
  • Its average width is 100 km.
  • The most significant feature of this plain is the Cauvery delta, which is 130 km wide.
  • The Cauvery delta is known for its fertile soil and large-scale irrigation facilities, which have made it the granary of South India.

Coastlines of Emergence and Submergence

• Coastline of emergence is formed by either uplift of land or lowering of sea level.
• Coastline of submergence is the opposite case of coastline of emergence.
• Emergence features include bars, spits, lagoons, salt marshes, beaches, sea cliffs, and arches.
• The east coast of India, particularly the southeast part (Tamil Nadu coast), is a coastline of emergence.
• The west coast of India is both emergent and submergent.
• The northern portion of the west coast is submerged due to faulting.
• The southern portion of the west coast, i.e., Kerala coast, is an example of a coastline of emergence.
• Coromandel coast (Tamil Nadu) is a coastline of emergence.
• Malabar coast (Kerala coast) is a coastline of emergence.
• Konkan coast (Maharashtra and Goa coast) is a coastline of submergence.

Significance of Indian Coastlines

• The coastlines of India extend up to 7516.6 km including the island groups Andaman and Nicobar and Lakshadweep.
• The coastal plains in India have a favorable climate with no extreme temperature which is ideal for human development.
• The coastal plains in India are mostly covered by fertile soils which are best for cultivations, with rice being the major crop cultivated in these regions.
• The ports along the Indian coastlines help in carrying out trade.
• The sedimentary rocks of these coastal plains contain large deposits of mineral oil which can be used as a source of marine economy.
• Fishing has become an important occupation of the people living in coastal areas.
• The coastal plains in India are rich in coastal and marine ecosystems which also include a wide range of mangroves, coral reefs, estuaries, and lagoons serving as great tourism potential.