Eastern coastal plain

Also called: East coast · Topic: Structure and Physiography of India: Himalayas, Plains, Peninsula, Coasts and Islands · NCERT: Class 7, Ch 1 "Geographical Diversity of India"; Class 11, Ch 2 "Structure and Physiography"

Meaning

The Eastern coastal plain (East coast) is a broad strip of low, flat land between the Eastern Ghats and the Bay of Bengal. It is an emergent coast (the land has risen, or the sea has fallen, so old sea floor now shows as flat, sandy land). Its parts are the Utkal plain (Odisha) in the north, the Northern Circars (Andhra Pradesh) in the middle and the Coromandel coast (Tamil Nadu) in the south.

It holds the large deltas of the Mahanadi, Godavari, Krishna and Kaveri. These are fertile, crowded rice-growing areas. The plain is also India's most cyclone-exposed coast and has fewer natural harbours than the west.

Explanation

How it formed: an emergent coast

• The land rose, so the plain is broad.
• Former sea floor came above the water.

• This left a wide strip of flat land. It is much wider than the western coastal plain.

• Long rivers built big deltas.

• The big Peninsular rivers flow east over a gentle slope. They are long and carry a lot of silt.
• At the river mouth, the river drops silt faster than the sea can carry it away. This builds a delta (a fan-shaped piece of land made of silt).

• From north to south, the deltas are the Mahanadi, Godavari, Krishna and Kaveri.

• Sand bars made lagoons.

• Waves and currents pile sand into bars, spits and ridges along the shore.
• These close off shallow water behind them and form lagoons, such as Chilika and Pulicat. A lagoon is shallow water cut off from the sea by a natural barrier such as a sand bar, spit or reef.

Why it has fewer natural harbours

• A shallow sea floor keeps big ships away from the shore.
• NCERT says the continental shelf extends up to 500 km into the sea. The continental shelf is the shallow, gently sloping sea floor at the edge of a continent, before the deep ocean begins.
• Silt from the deltas makes the water near the coast even shallower.

• Large ships cannot come close, so ports are hard to build and must be dredged (the silt dug out) again and again.

• Most east-coast ports are artificial or river ports.

• Chennai is an artificial harbour. Kolkata-Haldia is a river port on the Hugli.
• Visakhapatnam is the exception. It is a deep, naturally sheltered harbour.
• Even so, the east coast has six of India's 12 Major Ports, the same number as the west coast [5].

Parts of the plain (north → south)

Part	State	Key features
Utkal plain	Odisha	Mahanadi delta; Chilika lagoon; Paradip port
Northern Circars	Andhra Pradesh	Godavari and Krishna deltas; Visakhapatnam port
Coromandel coast	Tamil Nadu	Low and sandy; Kaveri delta; lagoons; Chennai port

Rain and hazards

• Coromandel gets most of its rain in October–December, not June–September.
• June–September: the coast stays fairly dry. It lies in the rain-shadow (the dry side of a mountain, away from the wind) of the Western Ghats. The south-west monsoon winds also blow parallel to this coast.

• October–December: the north-east monsoon (the retreating monsoon) picks up moisture over the Bay of Bengal and brings rain to the Tamil Nadu coast. Cyclones from the Bay of Bengal add heavy rain in the same months.

• The low, flat land lets sea water travel far inland.

• The plain is exposed to cyclones and storm surges (sea water pushed onto land by a storm's strong winds).
• The 2004 Indian Ocean tsunami struck the Coromandel coast. A tsunami is a series of very long, high sea waves caused by an undersea earthquake, landslide or volcano. Because the land is low, flat and sandy, the waves reached far inland and did heavy damage.

Where it occurs

• Location: along the Bay of Bengal, between the Eastern Ghats and the sea. It runs from Odisha through Andhra Pradesh to Tamil Nadu. Kolkata-Haldia in West Bengal is also counted among the east-coast ports.
• Deltas:
• Mahanadi (Odisha)
• Godavari and Krishna (Andhra Pradesh)

• Kaveri (Tamil Nadu)

• Lagoons:

• Chilika (Odisha): India's largest brackish-water lake (brackish means a mix of fresh and salt water). A long sandy ridge cuts it off from the Bay of Bengal, but sea water still flows in and out. Because of this, its salt level changes a lot with the seasons [4]. It became a Ramsar site on 1 October 1981 and covers 116,500 ha [4].

• Pulicat: on the Andhra Pradesh–Tamil Nadu border, north of Chennai.

• Ports (north → south):

Port	State	Note
Kolkata-Haldia	West Bengal	River port on the Hugli; Kolkata Port Trust renamed Syama Prasad Mookerjee Port (Cabinet approval, 2020) [6]
Paradip	Odisha	Near the Mahanadi delta
Visakhapatnam	Andhra Pradesh	Deep, naturally sheltered harbour
Chennai	Tamil Nadu	Artificial harbour
Kamarajar (Ennore)	Tamil Nadu	Renamed after K. Kamarajar, former Chief Minister of Tamil Nadu [7]
V.O. Chidambaranar (Tuticorin)	Tamil Nadu	Renamed in 2011 [7]

• Coastline context: India's total coastline is now 11,098.81 km, up from the old figure of 7,516.6 km [2][3]. The Ministry of Ports, Shipping and Waterways notified the new figure on 29 April 2025 [2].

Don't confuse with

• Western coastal plain: a submerged coast (the land sank). It is narrow, with estuaries, kayals and many natural harbours. The Eastern coastal plain is emergent: broad, with deltas, lagoons and fewer good harbours.
• Estuary vs delta: an estuary is a wide, funnel-shaped river mouth where the tide moves in and out, as on the Narmada and Tapi. A delta is a fan of silt built at the mouth, as on the Mahanadi, Godavari, Krishna and Kaveri. East-coast rivers make deltas.
• Northern Circars vs Utkal plain: the Northern Circars are in Andhra Pradesh. Odisha's coastal plain is the Utkal plain. Questions often place the Northern Circars in Odisha, which is wrong.
• Lagoon vs kayal: both are shallow water behind sand bars. Lagoons such as Chilika and Pulicat are on the east coast. Kayals (backwaters) such as Vembanad are on the Malabar coast in the west.

Prelims Hooks

• Order of parts, north → south: Utkal plain (Odisha) → Northern Circars (Andhra Pradesh) → Coromandel (Tamil Nadu).
• Deltas, north → south: Mahanadi → Godavari → Krishna → Kaveri. The Narmada and Tapi form estuaries, not deltas.
• Trap: the Coromandel coast gets most of its rain in October–December from the north-east monsoon and cyclones. It stays fairly dry in June–September.
• Chilika (Odisha): India's largest brackish-water lake. It became a Ramsar site on 1 October 1981 [4]. Pulicat lies on the Andhra Pradesh–Tamil Nadu border.
• Ports: Visakhapatnam is a deep natural harbour, Chennai is artificial and Kolkata-Haldia is a river port. Renamed ports: Tuticorin → V.O. Chidambaranar (2011) and Ennore → Kamarajar [7]; Kolkata → Syama Prasad Mookerjee [6].
• Swap trap: east = emergent, broad, with deltas. West = submerged, narrow, with estuaries. Each coast has six of the 12 Major Ports [5].

Mains Points

• How the type of coast shapes the economy (GS-I, GS-III):
• The emergent coast has broad deltas with fertile soil. This supports dense population and rice farming, and the Godavari, Krishna and Kaveri deltas are major rice bowls.

• But the wide, shallow continental shelf and heavy silting mean ports must be dredged often, which raises costs. Most ports are artificial or river ports, while Visakhapatnam is a natural one.

• Disaster exposure (GS-III Disaster Management):

• The low, flat plain faces cyclones and storm surges in October–December and tsunamis, such as the one in 2004 on the Coromandel coast.

• Key responses are coastal hazard mapping and natural protection such as mangroves and shelterbelts (rows of trees planted to break the force of wind and waves).

• Coastal wetlands and maritime planning (GS-III Environment, Infrastructure):

• Chilika is a Ramsar site [4], but it faces silting, changes in salt level, aquaculture and tourism pressure. Managing it carefully protects fisheries, birds and livelihoods.
• The revised coastline of 11,098.81 km [2] matters for coastal security, Coastal Regulation Zone planning, the blue economy and port-led growth under programmes such as Sagarmala.

Related concepts

• Coastal plains of India
• Western coastal plain
• Konkan coast
• Malabar Coast
• Kerala backwaters
• Coromandel Coast

Read more

• The Coastal Plains: a submerged west and an emergent east