The Coastal Plains of India Explained

The coastal plains of India are the low, fertile strips of land that run along the country’s western and eastern shores between the sea and the uplands behind, a narrow, broken plain on the Arabian Sea side and a broad, deltaic plain on the Bay of Bengal side. Together they stretch along a mainland coastline of roughly six thousand kilometres, and they hold some of India’s densest farming regions, its busiest ports, its most productive rice lands and its richest wetlands. Understanding why the two coasts look so different explains a great deal about Indian rivers, rainfall, cyclones and settlement.

The two plains are separated by the great triangle of the peninsular plateau, and they meet at the southern tip near Kanyakumari. This article, last reviewed on 4 November 2026, explains how the coastal plains formed, how the western and eastern plains differ, what lagoons and deltas they contain, and why they are both a gift and a hazard for the people who live on them.

Coastal Plains of India: Quick Facts

Key Takeaways

• India’s coastal plains are two separate lowland belts, a narrow western plain facing the Arabian Sea and a broad eastern plain facing the Bay of Bengal, divided by the peninsular plateau and joined at Kanyakumari.
• The western plain is narrow because the Western Ghats rise steeply close to the sea and short, fast rivers drop their sediment quickly, forming estuaries rather than deltas.
• The eastern plain is broad because long, sediment-heavy rivers such as the Mahanadi, Godavari, Krishna and Kaveri cross a gentle slope and build large deltas.
• The plains contain lagoons and backwaters, including Chilika and Pulicat on the east and the Vembanad system on the west, that support fisheries, migratory birds and tourism.
• The east coast is far more exposed to tropical cyclones, while the west coast gets heavy monsoon rain and faces rising cyclone activity in the Arabian Sea.
• Dense population, rice farming, ports and industry sit on the plains, which makes them highly vulnerable to storm surge, saltwater intrusion and sea-level rise.

What are the coastal plains of India and where are they?

The coastal plains of India are the lowland strips of sedimentary land lying between the coast and the hill ranges known as the Western Ghats and Eastern Ghats. They begin in Gujarat in the north-west, run south along the Arabian Sea to Kanyakumari, and then curve north along the Bay of Bengal as far as the Ganga delta in West Bengal. They cover the coastal districts of Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Puducherry, Andhra Pradesh, Odisha and West Bengal.

Geographers usually treat the two plains separately because their form is so different. The western coastal plain sits between the Western Ghats and the Arabian Sea, while the eastern coastal plain lies between the Eastern Ghats and the Bay of Bengal. The Western Ghats are a continuous, high escarpment, whereas the Eastern Ghats are a lower, broken series of hills cut by large rivers, which is a major reason why the eastern plain is so much broader and better connected to the interior.

The plains are not only a geological feature but also a map of human life in India. Many of the oldest ports, including Surat, Kochi, Kozhikode, Machilipatnam and Puducherry, grew on these plains, and the coastal belt supports a very large share of India’s rice, coconut, fish and spice production.

How did the coastal plains form?

The coastal plains formed through a combination of tectonic movement along the old edges of the peninsula and the slow deposit of river sediment and marine material over millions of years. The two coasts have very different histories. The western edge of the peninsula is thought to have been shaped by faulting and uplift when the Indian landmass separated from Madagascar and the Seychelles, a process that left a steep scarp, the Western Ghats, right next to the sea. That scarp left little room for a wide plain.

The eastern coast, by contrast, is a passive margin where the land slopes gently toward the Bay of Bengal. Rivers flowing east from the plateau cross this long gentle slope, slow down and drop their loads of silt, sand and gravel. Over geological time, this dropped sediment has built wide plains and extended the coastline seaward. The sea level has also swung up and down during the ice ages, repeatedly flooding and exposing the coastal margin, and shaping beaches, lagoons and sand ridges.

Textbooks often describe the western coast as a coast of submergence, partly drowned by the sea, and the eastern coast as a coast of emergence, built outward by deposition and local uplift. This is a useful simplification, though real coasts show both processes in different places and modern geologists treat the description as a general tendency rather than a rule.

Why is the western coastal plain narrow?

The western coastal plain is narrow because the Western Ghats rise steeply close to the Arabian Sea, leaving only a thin strip of low land, and because the rivers draining west are short, fast and carry little room to build large deltas. Along much of the Konkan the plain is only a few tens of kilometres wide at most, and in places the hills reach almost to the water. Further south, in Kerala, the plain broadens somewhat but remains modest compared with the eastern side.

The western coast is conventionally divided into four parts. The Gujarat plain in the north includes the Kathiawar peninsula and the Gulf of Khambhat, with its muddy tidal flats, and the alluvial lowland of the Narmada and Tapi. The Konkan coast runs from Daman to Goa and is rugged, with rocky headlands, cliffs and small beaches. The Kanara or Karavali coast runs from Goa to Mangalore and has small river mouths and sandy bars. The Malabar coast, from Mangalore to Kanyakumari, is famous for its lagoons, sandy spits and backwaters.

The soils of the western plain are often lateritic, particularly in the Konkan, formed under intense monsoon rainfall that leaches the rock. They are good for cashew, mango, coconut and spices rather than for large-scale grain farming. The heavy rainfall, often exceeding two to three metres a year along the central part of the coast, feeds dense forests on the Ghats slopes and paddy fields on the narrow lowlands.

Why is the eastern coastal plain broad?

The eastern coastal plain is broad because the Eastern Ghats lie further inland and the long rivers of the peninsula carry large amounts of sediment across a gentle slope, building deltas as they meet the Bay of Bengal. In the major delta regions the plain can extend well over a hundred kilometres inland, and it is much flatter and more continuous than the western strip.

Geographers divide the eastern plain into three parts. The Utkal plain in Odisha lies between the Subarnarekha and the Rushikulya and includes the Mahanadi delta and the Chilika lagoon. The Andhra plain, historically called the Northern Circars, runs from the Rushikulya to Pulicat and contains the Godavari and Krishna deltas, among the most productive rice-growing lands in the country. The Tamil Nadu plain, called the Coromandel coast, runs from Pulicat to Kanyakumari and includes the Kaveri delta, long known as the rice bowl of the south.

The eastern plain has deep alluvial soils that are well suited for rice, sugarcane, pulses and oilseeds, and a dense network of canals developed in the nineteenth century to irrigate the deltas. Because the rivers carry more silt, the coastline has grown seaward in places. At the same time, many deltas are now sinking relative to the sea as dams trap sediment upstream and groundwater is withdrawn, an issue discussed further below.

How do the western and eastern coastal plains compare?

The two plains differ in width, river type, landforms, rainfall and hazard, and the table below sets out the main contrasts at a glance.

One way to remember the difference is that the western plain is a plain of short rivers meeting a steep wall, and the eastern plain is a plain of long rivers meeting a gentle slope.

What are the lagoons and backwaters of the coastal plains?

Lagoons and backwaters are shallow coastal water bodies separated from the open sea by sandbars or spits, and India’s coastal plains contain several of the best known in Asia. On the east, Chilika Lake in Odisha is the largest coastal lagoon in India and one of the largest brackish-water lagoons in the world, home to a great number of wintering migratory birds and to the Irrawaddy dolphin. Pulicat Lake, on the border of Andhra Pradesh and Tamil Nadu, is the second largest brackish lagoon in the country and a major flamingo and wader site.

On the west, the Kerala backwaters form a network of lagoons, lakes, canals and estuaries running parallel to the coast. The Vembanad lake is the largest, and Ashtamudi and Sasthamkotta are other notable water bodies. These waters support fishing, coir making, rice farming below sea level in the Kuttanad region, and a large tourism sector. Further north, the Gulf of Khambhat and the Gulf of Kutch have broad tidal flats and mangroves of their own.

Lagoons form when a sand barrier builds up across a bay or river mouth, trapping water behind it. They are shallow, productive and very sensitive. Siltation, upstream pollution, reduced freshwater inflow and encroachment all threaten them, and several are protected as Ramsar wetlands of international importance, including Chilika, Ashtamudi and Vembanad-Kol.

What are the deltas of the coastal plains?

The deltas of India’s coastal plains are fan-shaped lowlands built from river sediment at the sea, and the major ones are those of the Ganga-Brahmaputra, Mahanadi, Godavari, Krishna and Kaveri rivers. The Ganga-Brahmaputra delta at the head of the Bay of Bengal, shared with Bangladesh, is the largest delta in the world and includes the Sundarbans, the largest mangrove forest on Earth. The Mahanadi delta in Odisha is a network of distributaries and rich paddy land. The Godavari and Krishna deltas in Andhra Pradesh are sometimes called the granary of the south, while the Kaveri delta in Tamil Nadu has been irrigated for nearly two thousand years, since the Grand Anicut was built in the early centuries of the common era.

Deltas are naturally dynamic. Rivers shift channels, floods spread fertile silt, and the shoreline advances or retreats with the balance between river sediment and sea waves. But the sediment supply is now falling in many Indian deltas because dams and barrages trap it upstream. At the same time, sea level is rising and groundwater withdrawal causes land to sink. Studies suggest that several Indian deltas, including the Sundarbans, are losing ground in places, though rates vary and are still being refined.

Deltaic mangroves, such as those of the Sundarbans, Bhitarkanika and Godavari, act as natural buffers that reduce the force of cyclone waves and protect the coast. Their loss to aquaculture ponds and land reclamation raises the risk for the communities living behind them.

Why do the coastal plains matter for people and the economy?

The coastal plains matter because they combine fertile soil, water, ports and fisheries, and so concentrate a very large share of India’s population and economic activity. The deltas are among the most intensively farmed rice lands in the country. The narrow western plain, with its harbours at Mumbai, Kochi, Mangalore and Kandla, handles a great deal of India’s trade. The east coast ports of Visakhapatnam, Chennai, Paradip and Kolkata serve the mineral-rich interior and the growing industrial belt.

Coastal plains also support marine fishing, salt production, coconut and cashew plantations, and a large and growing tourism sector built on beaches, lagoons and backwaters. Millions of small-scale fishers live in villages on the shore, and their livelihoods depend on healthy estuaries, mangroves and nearshore waters.

Because many of India’s largest cities, including Mumbai, Chennai, Kolkata and Visakhapatnam, sit at or near sea level, the plains also concentrate infrastructure and people in the path of coastal hazards. This is a defining tension: the very land that offers the best soil and trade access is also the land most exposed to storms and the sea.

What hazards threaten the coastal plains?

The main hazards on the coastal plains are tropical cyclones with storm surge, floods, coastal erosion, saltwater intrusion and, increasingly, sea-level rise. The east coast takes the brunt of cyclones, since most of the storms in the north Indian Ocean form in the Bay of Bengal and cross the coast of Odisha, Andhra Pradesh, Tamil Nadu or West Bengal. The Odisha coast in particular has suffered several devastating storms, including the 1999 super cyclone, though improved forecasts and cyclone shelters have since sharply reduced loss of life.

The west coast has historically seen fewer cyclones, but Arabian Sea storms have become more frequent and intense in recent years, and cyclones such as Tauktae in 2021 and Biparjoy in 2023 affected the Gujarat and Konkan coasts. Heavy monsoon rain also brings floods and landslides to the western plain, as seen in the 2018 Kerala floods.

The 2004 Indian Ocean tsunami showed the vulnerability of the eastern and southern coastline, with Tamil Nadu, Andhra Pradesh, Puducherry and the Andaman and Nicobar Islands badly affected. Long-term erosion is another concern, with stretches of the Kerala, Odisha and Tamil Nadu coasts losing beach to waves. Government assessments have reported that a notable fraction of India’s shoreline is under erosion, though the extent varies by source and period.

How can the coastal plains be protected?

The coastal plains are best protected by combining natural defences, careful planning and early warning, rather than relying on hard walls alone. Mangrove, dune and shelterbelt restoration can reduce wave energy and erosion at low cost. Coastal regulation rules, which restrict construction near the high tide line, aim to keep development out of the most vulnerable strip, though enforcement is often uneven.

Early-warning systems and cyclone shelters have been one of India’s biggest success stories, especially in Odisha and Andhra Pradesh. Managing river sediment, restoring freshwater flow into deltas and limiting groundwater extraction can slow land subsidence and saltwater intrusion. Planning for sea-level rise, including raising critical infrastructure and avoiding new development in the lowest areas, is increasingly seen as essential.

Bottom Line

The coastal plains of India are two very different lowlands: a narrow, broken western plain squeezed between the Western Ghats and the Arabian Sea, and a broad, deltaic eastern plain built by long rivers meeting the Bay of Bengal. They hold lagoons, backwaters, mangroves, fertile rice lands and great ports, and they shelter a large share of the Indian population. Their future depends on managing storms, rising seas and shrinking river sediment with care.

Frequently Asked Questions

Why is the western coastal plain narrower than the eastern one?

The Western Ghats rise steeply close to the Arabian Sea and the rivers draining west are short and fast, so they leave little room for a wide plain. The eastern coast has a gentle slope and long rivers that build broad deltas.

What are the divisions of the western coastal plain?

It is usually divided into the Gujarat plain, the Konkan coast (Daman to Goa), the Kanara or Karavali coast (Goa to Mangalore) and the Malabar coast (Mangalore to Kanyakumari).

What is the Coromandel Coast?

The Coromandel Coast is the southern part of the eastern coastal plain in Tamil Nadu, running roughly from Pulicat to Kanyakumari. It includes the Kaveri delta and receives much of its rain from the northeast monsoon in October to December.

Which are the largest lagoons in India?

Chilika Lake in Odisha is the largest coastal lagoon in India, followed by Pulicat Lake on the Andhra Pradesh and Tamil Nadu border. The Vembanad lake is the largest of the Kerala backwaters.

Why do cyclones hit the east coast more often than the west coast?

Most north Indian Ocean cyclones form over the warm waters of the Bay of Bengal and move toward the east coast. The Arabian Sea sees fewer storms, although their frequency and intensity have been rising in recent years.

What are the Northern Circars?

The Northern Circars are the northern part of the eastern coastal plain, covering the coast of Andhra Pradesh from roughly the Odisha border down to the Krishna delta. The name is a historical term, and the region includes the fertile Godavari and Krishna deltas.

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