Topic 4: The Northern Plains & Coastal Plains of India

Between the Himalayas and the Peninsular Plateau lies the Great Plains of India — a vast alluvial trough built by the Indus, Ganga and Brahmaputra, and home to a large share of India's people. This chapter traces the plains from their origin (a Himalayan foredeep filled with sediment) through the four N–S belts — Bhabar, Tarai, Bhangar, Khadar — and the four meso-regions (Rajasthan, Punjab–Haryana, Ganga, Brahmaputra plains). It then follows India's two coastal plains — the wide deltaic Eastern coast and the narrow Western (Konkan–Malabar) coast — plus the Rann of Kutch, deltas and estuaries. With labelled diagrams, tables and PYQs + full model answers.

UPSC Prelims · Mains GS-I Bhabar · Tarai · Bhangar · Khadar ~35 min read Great Plains · Coastal Plains Very High Weight

1.The Great Plains — Overview & Significance
2.Origin of the Great Plains
3.Four N–S Belts: Bhabar, Tarai, Bhangar, Khadar
4.The Four Meso-Regions
5.The Ganga Plain in Detail
6.The Eastern Coastal Plain
7.The Western Coastal Plain & Rann of Kutch
8.Eastern vs Western Coast: Deltas & Estuaries
9.Economic & Agricultural Significance
10.Problems & GS-I Synthesis
11.Current Affairs Link
12.Prelims PYQs
13.Mains PYQs + Model Answers
★15-Minute Revision Box

Conceptual Clarity — Why this Chapter Matters

The plains are India's demographic and agricultural heartland — and a Prelims favourite for its neat terminology. Sort your prep three ways:

Definitional / static: the N–S sequence Bhabar → Tarai → Bhangar → Khadar; what each means (Bhabar = pebbly porous piedmont, Tarai = marshy re-emergence zone, Bhangar = old alluvium with kankar, Khadar = new flood-plain alluvium); the four meso-regions; Doab meaning.
Statement-elimination: "Bhabar streams disappear underground", "Tarai is marshy", "Khadar is renewed every flood", coastal-plain pairings (Konkan/Malabar = west; Northern Circars/Coromandel = east), Rann of Kutch salt-marsh.
Applied / synthesis (Mains GS-I & GS-III): why the plains carry such dense population, the flood–waterlogging–groundwater problems, and the contrast between deltaic east and estuarine west coasts. Needs idea + example + judgement.

Territorial note: India's plains and coasts extend across the entire sovereign territory. The LoC and LAC are not settled international borders.

1. The Great Plains — Overview & Significance

The Great Plains of India (Indo-Gangetic–Brahmaputra plain) is a vast, level lowland formed by the alluvium of three river systems — the Indus, Ganga and Brahmaputra. It stretches ~3,200 km W–E, ~150–300 km wide, covering ~7 lakh km².

Occupies ~22.9% of India's area but supports a very large share of its population.
Depth of alluvium reaches up to ~2,000–6,000 m over a buried Peninsular basement.
Extremely gentle gradient — the fall from Delhi to the Bay of Bengal is only ~200 m over ~1,500 km, so rivers meander widely.

Feature	Detail
Extent	~3,200 km W–E; 150–300 km wide
Area	~7 lakh km² (~22.9% of India)
Rivers	Indus, Ganga, Brahmaputra + tributaries
Soil	Deep, fertile alluvium (Bhangar + Khadar)

GS-I hook: flat relief + fertile alluvium + perennial Himalayan rivers = India's granary and its most densely settled region. Every later topic on agriculture, population and rivers leans on this base.

2. Origin of the Great Plains

The plains occupy a foredeep — a depression that formed in front of the rising Himalaya as the Indian plate bent down under the load. Several theories explain how this trough was filled; they are complementary, not rival.

Theory	Core idea
Alluviation of the foredeep (widely accepted)	A sag/foredeep formed south of the Himalaya; rivers filled it with alluvium.
Infilling of a rift valley	The plain sits over a down-faulted rift between Himalaya & Peninsula, later filled.
Recession of the sea	An arm of the sea once occupied the site and was silted up as the shoreline retreated.
Remnant of the Tethys	The plain is the last, silted-up remnant of the ancient Tethys geosyncline.

Clarity: the mainstream view (Sir Sydney Burrard / modern geology) is the foredeep model — a flexural sag ahead of the Himalaya, continuously filled by prolific Himalayan sediment. The others describe aspects of the same basin's history.

3. The Four N–S Belts: Bhabar, Tarai, Bhangar, Khadar

Moving from the Himalayan foothills southward, the plain changes character in four parallel belts — the single most tested idea in this chapter.

Fig 4.1 — The four N→S belts: coarse porous Bhabar at the foothills, marshy Tarai where water re-emerges, older Bhangar uplands with kankar, and the fresh flood-renewed Khadar along the rivers.

Belt	Position	Character
Bhabar	Foot of Shiwaliks (8–16 km wide)	Coarse pebbles/gravel (piedmont); porous — streams disappear underground; unfit for crops
Tarai	South of Bhabar (15–30 km)	Marshy, damp; underground streams re-emerge; once malarial forest, now reclaimed farmland
Bhangar	Older upland alluvium	Above flood level; darker, contains lime nodules (kankar); forms terraces
Khadar	New alluvium along rivers	Low-lying flood-plain; renewed by silt each flood; very fertile

Prelims anchor: Bhabar = porous & streams vanish; Tarai = marshy & streams re-appear; Bhangar = old + kankar; Khadar = new + renewed each flood. The N–S order Bhabar→Tarai→Bhangar→Khadar is the classic sequence question.

4. The Four Meso-Regions of the Northern Plains

Along the W–E axis the Great Plain divides into four meso-regions, each tied to a river system.

Meso-region	Rivers	Key features
Rajasthan Plain	Luni (only major); Thar	Arid; Marusthali & Bagar; playas (salt lakes e.g. Sambhar)
Punjab–Haryana Plain	Indus tributaries (Sutlej, Beas, Ravi)	Built of Doabs (land between two rivers); Bari, Bist, Malwa doabs; "Land of five rivers"
Ganga Plain	Ganga + Yamuna, Ghaghara, Gandak, Kosi	Largest; Upper/Middle/Lower divisions; densely farmed & peopled
Brahmaputra Plain	Brahmaputra	Assam valley; braided channel; Majuli (large river island); flood-prone

Term to know — Doab: "do-ab" = "two waters" — the fertile alluvial land between two rivers (e.g. the Ganga–Yamuna Doab). A staple Prelims term from the Punjab–Haryana plain.

5. The Ganga Plain in Detail

The Ganga Plain is the largest meso-region — from Delhi to the Bengal delta — and is conventionally split into three:

Upper Ganga Plain: Ganga–Yamuna Doab, Rohilkhand; higher, drier, canal-irrigated (sugarcane, wheat).
Middle Ganga Plain: eastern UP & Bihar; Ghaghara, Gandak, Kosi join; frequent floods (the Kosi = "Sorrow of Bihar").
Lower Ganga Plain: West Bengal & the Bengal delta; deltaic distributaries, the Sundarbans mangroves, moribund vs active delta.

Sub-division	Signature
Upper Ganga Plain	Doab; canal irrigation; sugarcane belt
Middle Ganga Plain	Kosi/Gandak floods; fertile but flood-hit
Lower Ganga Plain	Bengal delta; Sundarbans; rice & jute

Note: the Kosi shifts its course westward dramatically, depositing sand and causing repeated floods — hence "Sorrow of Bihar." The Bengal delta is the world's largest, shared with Bangladesh.

6. The Eastern Coastal Plain

Between the Eastern Ghats and the Bay of Bengal runs a broad, gently-sloping emergent coastal plain, built largely by the deltas of the east-flowing peninsular rivers.

Width: wide (~80–100 km) — broader than the west coast.
Nature: an emergent coast (uplifted) — gentle, straight, with lagoons, sandbars and few good natural harbours.
Deltas: the Mahanadi, Godavari, Krishna and Kaveri build large fertile deltas — hence the alternate name "the deltaic coast."

Segment	Location	Signature
Utkal Plain	Odisha coast	Mahanadi delta; Chilika lagoon (largest brackish lagoon in India)
Northern Circars	Andhra (north)	Godavari–Krishna deltas; broad, fertile
Coromandel Coast	Tamil Nadu	Kaveri delta ("granary of the south"); gets NE-monsoon (winter) rain

Prelims anchors: Chilika (Odisha) = largest coastal lagoon & a Ramsar site; Pulicat (AP–TN) = second-largest lagoon, with Sriharikota (SHAR) on its bar; Coromandel is watered by the retreating (NE) monsoon, so TN's rain peak is Oct–Dec.

7. The Western Coastal Plain & the Rann of Kutch

Between the Western Ghats and the Arabian Sea lies a narrow, steep submergent coastal plain — the opposite character to the east.

Width: narrow (~10–80 km), squeezed against the Ghats.
Nature: a submergent coast — indented, with estuaries, cliffs and excellent natural harbours (Mumbai, Marmagao, Kochi, Mangaluru).
Rivers: short, swift, west-flowing rivers form estuaries, not deltas (Narmada & Tapi drown their mouths).

Segment (N→S)	Location	Signature
Kachchh & Kathiawar	Gujarat	Great & Little Rann salt-marsh; wild ass sanctuary; flamingos
Konkan Coast	Maharashtra–Goa	Rocky, indented; Mumbai harbour; rice & cashew
Kanara Coast	Karnataka	Narrow; Marmagao, New Mangaluru ports
Malabar Coast	Kerala	Backwaters (kayals) — Vembanad, Ashtamudi; coir, spices

Rann of Kutch: a vast seasonal salt-marsh — sea in the SW monsoon, salt-encrusted desert in the dry season. The Great Rann hosts the only Indian population of the wild ass and huge flamingo colonies; the Little Rann is a key saltpan zone. It lies wholly within Indian territory (Gujarat).

Kerala backwaters (kayals): a chain of lagoons and lakes parallel to the coast — Vembanad (longest lake in India) and Ashtamudi are Ramsar wetlands supporting inland navigation, tourism and the Nehru Trophy boat race.

8. Eastern vs Western Coast: Deltas & Estuaries

The two coasts are near-mirror opposites — a favourite comparison for both Prelims elimination and a Mains diagram. The contrast flows from one fact: the east coast is emergent and river-fed (deltas), the west coast is submergent and estuarine.

Fig 4.2 — Schematic contrast: the narrow, steep, estuarine west coast vs the broad, gentle, deltaic east coast (not to scale; illustrative cross-profile).

Feature	Eastern Coast	Western Coast
Nature	Emergent (uplifted)	Submergent (drowned)
Width	Broad (80–100 km)	Narrow (10–80 km)
River mouths	Large deltas	Estuaries (Narmada, Tapi)
Harbours	Few natural (mostly artificial)	Many good natural (Mumbai, Kochi)
Coastline	Straight, lagoon-fringed	Indented, rocky, cliffed
Names	Utkal, N. Circars, Coromandel	Kachchh, Konkan, Kanara, Malabar
Water bodies	Chilika, Pulicat lagoons	Vembanad, Ashtamudi backwaters

One-line logic: West = submergent → estuaries & harbours; East = emergent → deltas & lagoons. Narmada & Tapi are the only large peninsular rivers to form estuaries because they flow through rift valleys into the Arabian Sea.

9. Economic & Agricultural Significance

The plains and coasts together form India's productive core — a direct consequence of deep, renewable alluvium, level land and water availability.

Agriculture: the Indo-Gangetic plain is the country's granary (wheat, rice, sugarcane, jute); Khadar renews fertility every flood; the deltas grow rice.
Irrigation: perennial Himalayan rivers + high water-table make canal and tube-well irrigation easy — the Green Revolution heartland (Punjab, Haryana, W. UP).
Settlement & transport: flat land supports dense population, roads, railways and the largest cities; navigable rivers aided historic trade.
Coasts: natural harbours (west) drive port trade; fisheries, salt (Rann, TN), backwater tourism and coastal industry.

Endowment	Economic pay-off
Deep renewable alluvium	High, sustained crop yields (granary of India)
Perennial rivers + high water-table	Assured irrigation → Green Revolution
Level land	Dense settlement, cheap rail/road construction
Natural harbours (west)	Major ports (Mumbai, Kochi, Marmagao)
Deltas & backwaters	Rice bowls, fisheries, tourism

10. Problems & GS-I Synthesis

The very fertility and flatness that make the plains valuable also make them hazard-prone — a classic Mains "significance and challenges" framing.

Floods: low gradient + monsoon-fed rivers (Kosi, Ghaghara, Brahmaputra) cause recurrent, damaging floods; the Bengal delta and Brahmaputra plain are worst-hit.
Waterlogging & salinity: over-irrigation in canal tracts (Punjab, Haryana) raises the water-table, causing waterlogging and salt-encrustation (reh/kallar).
Groundwater depletion: intensive tube-well use in the north-west has caused among the world's fastest water-table declines.
Coastal hazards: cyclones & storm surges (east coast), coastal erosion, saltwater intrusion, and pressure on mangroves (Sundarbans).
Bank erosion & river shifting: the Kosi and Brahmaputra shift course and erode banks, displacing communities.

GS-I synthesis: the Great Plains are India's demographic and agricultural heartland — but sustaining them needs flood management, groundwater regulation, drainage against waterlogging, and coastal-zone protection. The single logic of the chapter: alluvial flatness = fertility + density, but also flood + waterlogging + subsidence risk.

11. Current Affairs & Contemporary Relevance (2024–2026)

The plains and coasts stay "current" through floods, groundwater stress, coastal-zone rules and river-management projects — verify the latest status before the exam. check for latest update or data

11.1 Floods & river management

Kosi & Brahmaputra floods: near-annual flooding in Bihar and Assam keeps embankment policy, silt management and India–Nepal/China data-sharing in the news; the Kosi High Dam and flood-forecasting upgrades recur. check for latest update or data

Groundwater depletion: CGWB and satellite (GRACE) data show the north-western plains among the fastest-depleting aquifers globally — driving the Atal Bhujal Yojana and micro-irrigation push. check for latest update or data

11.2 Coastal-zone & delta issues

CRZ & blue economy: Coastal Regulation Zone norms, the Sagarmala port programme and Sundarbans/mangrove protection tie the coastal plains to live policy debates on development vs ecology. check for latest update or data

11.3 Why it matters

Development	Why it matters for UPSC
Kosi/Brahmaputra floods	Links plain physiography to disaster management (GS-I & GS-III).
Atal Bhujal Yojana	Groundwater governance in the Green-Revolution plains.
Sagarmala & CRZ	Coastal-plain harbours & the development–ecology balance.
Sundarbans / mangroves	Deltaic coast, cyclone buffer, climate adaptation.

Recurring exam hooks:

Bhabar–Tarai–Bhangar–Khadar sequence · Doab · meso-regions (evergreen Prelims).
East vs west coast (emergent/submergent, deltas/estuaries, harbours) — near-certain elimination set.
Plains: fertility vs flood/waterlogging/groundwater (evergreen Mains GS-I).

12. Prelims PYQs (exam-style, high-frequency themes)

Objective questions anchored to genuinely tested UPSC themes on India's plains and coasts. Each carries a worked rationale.

UPSC Prelims — exam-style

Q: The narrow belt of pebble-studded porous piedmont where Himalayan streams disappear underground is called:

(a) Bhabar
(b) Tarai
(c) Bhangar
(d) Khadar

Answer: (a) Bhabar — the pebbly, highly porous piedmont just south of the Shiwaliks where streams sink underground; they re-emerge in the marshy Tarai just to the south.

UPSC Prelims — exam-style

Q: The "Khadar" of the northern plains refers to:

(a) Old alluvium with kankar nodules
(b) New alluvium renewed by floods each year
(c) Pebbly piedmont deposits
(d) Marshy re-emergence zone

Answer: (b) Khadar = the new, lighter, more fertile flood-plain alluvium renewed each flood; Bhangar is the older, terrace alluvium with lime nodules (kankar).

UPSC Prelims — exam-style

Q: A "Doab" in the northern plains is:

(a) A marshy tract along the foothills
(b) The land between two converging rivers
(c) An abandoned river channel
(d) A saline patch in the plains

Answer: (b) "Do-ab" = "two waters" — the interfluve between two rivers; the Ganga–Yamuna Doab is the classic example.

UPSC Prelims — exam-style

Q: Which of the following correctly pairs the coast with its character?

(a) Eastern coast — submergent, estuaries
(b) Western coast — submergent, estuaries
(c) Western coast — emergent, deltas
(d) Eastern coast — narrow, cliffed

Answer: (b) The western coast is submergent with estuaries (Narmada, Tapi) and good natural harbours; the eastern coast is emergent, broad and deltaic.

UPSC Prelims — exam-style

Q: The Chilika lake is best described as:

(a) India's largest brackish-water coastal lagoon (Odisha)
(b) A freshwater tectonic lake in Kerala
(c) A salt lake in the Rann of Kutch
(d) An oxbow lake of the Ganga

Answer: (a) Chilika, on the Utkal (Odisha) coast, is India's largest brackish coastal lagoon and a Ramsar site; Pulicat (AP–TN) is the second-largest.

UPSC Prelims — exam-style

Q: Consider the following statements about the Rann of Kutch:

1. It is a seasonal salt-marsh that floods in the SW monsoon.
2. The Great Rann is the only Indian habitat of the wild ass.
3. It lies in the state of Rajasthan.

Which are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (a) 1 and 2 only. Statement 3 is wrong — the Rann lies in Gujarat, not Rajasthan. (The wild ass sanctuary is in the Little Rann.)

UPSC Prelims — exam-style

Q: The Kerala "backwaters" (kayals) such as Vembanad and Ashtamudi are found along the:

(a) Coromandel Coast
(b) Northern Circars
(c) Malabar Coast
(d) Utkal Coast

Answer: (c) Malabar Coast (Kerala). Vembanad is India's longest lake; both Vembanad and Ashtamudi are Ramsar wetlands.

UPSC Prelims — exam-style

Q: The Coromandel coast receives most of its rainfall from:

(a) The SW (advancing) monsoon
(b) The NE (retreating) monsoon
(c) Western disturbances
(d) Convectional pre-monsoon storms only

Answer: (b) The NE (retreating/winter) monsoon — so Tamil Nadu's rainfall peaks in Oct–Dec, unlike most of India which peaks in the SW monsoon.

Prelims — anticipated themes

Likely: Bhabar–Tarai–Bhangar–Khadar N–S order & meaning · Doab · meso-regions (Rajasthan/Punjab–Haryana/Ganga/Brahmaputra) · east vs west coast pairings (emergent/submergent, delta/estuary, harbour) · Chilika/Pulicat lagoons · Vembanad backwaters · Rann of Kutch (Gujarat, wild ass) · Narmada–Tapi estuaries · Coromandel & NE monsoon. check for latest update or data

13. Mains PYQs + Model Answers

Genuine UPSC GS-I themes on India's plains and coasts and their human-geographic consequences. Each carries a full answer skeleton — Introduction → body → Conclusion.

UPSC Mains GS-I — style 15 marks · 250 words

Q: The Northern Plains are India's demographic and agricultural heartland. Examine the physiographic reasons and the challenges this concentration brings.

Model Answer

Introduction: the Indo-Gangetic–Brahmaputra plain occupies ~23% of India's area but supports a very large share of its people — a concentration rooted in its physiography.
Why fertile & dense: deep renewable alluvium (Khadar), level land, perennial Himalayan rivers and a high water-table give assured harvests and easy irrigation — the Green Revolution heartland.
Why settled: flatness allows dense villages, cheap roads/rail and India's largest cities, aided historically by navigable rivers.
Challenges: recurrent floods (Kosi, Brahmaputra), waterlogging & salinity from over-irrigation, and among the world's fastest groundwater depletion in the NW.
Conclusion: the same alluvial flatness that made the plains a heartland now demands flood control, groundwater regulation and drainage — sustaining the core is a national priority.

UPSC Mains GS-I — style 15 marks · 250 words

Q: Compare and contrast the Eastern and Western coastal plains of India with respect to their formation, character and economic use.

Model Answer

Introduction: India's two coasts are near-mirror opposites, a contrast driven by one fact — the east is emergent and river-fed, the west submergent and estuarine.
Formation: the eastern coast rose (emergent) and was built out by the deltas of the Mahanadi–Godavari–Krishna–Kaveri; the western coast subsided (submergent), drowning river mouths into estuaries.
Character: east = broad, straight, lagoon-fringed (Chilika, Pulicat), few natural harbours; west = narrow, indented, cliffed, with backwaters (Vembanad) and fine natural harbours.
Economic use: east = deltaic rice bowls (Kaveri "granary of the south"); west = port trade (Mumbai, Kochi), fisheries, spices, backwater tourism, Rann salt.
Conclusion: emergent-vs-submergent geology explains the whole contrast — deltas & lagoons in the east, estuaries & harbours in the west — shaping distinct economies.

UPSC Mains GS-I — style 15 marks · 250 words

Q: Discuss the origin of the Great Plains of India and explain the N–S sequence of Bhabar, Tarai, Bhangar and Khadar.

Model Answer

Introduction: the Great Plains are an alluvial fill of a foredeep (a downwarp between the rising Himalaya and the rigid Peninsula), formed by Indus–Ganga–Brahmaputra sediment.
Origin: the mainstream foredeep-alluviation view sees a subsiding trough progressively filled with debris; alternative rift-infilling and sea-recession ideas exist but are less favoured.
Bhabar & Tarai: just south of the Shiwaliks lies the pebbly, porous Bhabar where streams sink underground; they re-emerge in the marshy Tarai belt further south.
Bhangar & Khadar: away from the foothills, Bhangar is the older terrace alluvium with kankar nodules; Khadar is the newer flood-plain alluvium renewed each flood — the most fertile.
Conclusion: the neat N–S sequence records the plain's building history — coarse piedmont near the mountains grading to fine, renewed alluvium in the flood plains.

UPSC Mains GS-I — style 15 marks · 250 words

Q: "The fertility of the Northern Plains is inseparable from their flood and waterlogging problems." Critically examine.

Model Answer

Introduction: the plains' fertility and their hazards spring from the same source — a low-gradient alluvial surface fed by monsoon-swollen rivers.
Fertility side: annual flooding deposits nutrient-rich Khadar silt, sustaining the granary of India without exhausting the soil.
Hazard side: the same low gradient causes rivers (Kosi, Ghaghara, Brahmaputra) to overflow and shift, while canal over-irrigation raises the water-table into waterlogging and salinity.
Balance: embankments, better drainage, watershed and groundwater management, and flood-forecasting can retain the fertility benefit while cutting the damage.
Conclusion: floods are both maker and menace of the plains — the policy task is to manage, not eliminate, the river–silt system.

UPSC Mains GS-I — style 10 marks · 150 words

Q: Bring out the significance of the Rann of Kutch and the Kerala backwaters in India's physical and economic geography.

Model Answer

Introduction: both are distinctive coastal-plain features — the Rann a seasonal salt-marsh in Gujarat, the backwaters a lagoon chain in Kerala.
Rann of Kutch: floods in the monsoon, dries to salt desert; supports the wild ass, flamingo colonies and major saltpans (Little Rann); strategically a border zone.
Kerala backwaters: Vembanad (India's longest lake) & Ashtamudi are Ramsar wetlands sustaining inland navigation, fisheries, coir and tourism.
Conclusion: both show how coastal-plain landforms translate directly into ecology, livelihoods and revenue — and both need protection from salinity, pollution and encroachment.

Mains — anticipated themes

Likely: plains as demographic/agricultural heartland & its challenges · east vs west coast comparison · origin of the plains + Bhabar–Tarai–Bhangar–Khadar · fertility vs flood/waterlogging · groundwater depletion in the NW plains · significance of Rann/backwaters/deltas. check for latest update or data

15-Minute Revision Box

Must-Remember Facts — The Northern & Coastal Plains

The plains framework:

Built by Indus · Ganga · Brahmaputra; ~22.9% of area; foredeep fill
N–S belts: Bhabar → Tarai → Bhangar → Khadar
Bhabar = pebbly porous piedmont (streams sink)
Tarai = marshy re-emergence zone
Bhangar = old alluvium + kankar; Khadar = new flood alluvium

Meso-regions & rivers:

Rajasthan · Punjab–Haryana · Ganga · Brahmaputra plains
Doab = land between two rivers (Ganga–Yamuna)
Kosi = "Sorrow of Bihar"; Bengal delta = world's largest

Coasts (Prelims gold):

East = emergent, broad, deltas, lagoons (Chilika, Pulicat)
West = submergent, narrow, estuaries, harbours
West segments: Kachchh · Konkan · Kanara · Malabar
East segments: Utkal · N. Circars · Coromandel
Narmada & Tapi = estuaries (rift valleys)

Water bodies & oddities:

Chilika = largest lagoon; Vembanad = longest lake
Rann of Kutch = Gujarat salt-marsh, wild ass
Coromandel = NE-monsoon rain (Oct–Dec)

Highest-frequency themes: Bhabar–Tarai–Bhangar–Khadar order · Doab · east vs west coast (emergent/submergent, delta/estuary, harbour) · Chilika/Pulicat/Vembanad · Rann of Kutch (Gujarat) · Narmada–Tapi estuaries. One logic: alluvial flatness = fertility + density, but also flood + waterlogging; west submergent = estuaries & harbours, east emergent = deltas & lagoons.

Belt	Character
Bhabar	Pebbly, porous
Tarai	Marshy
Bhangar	Old alluvium (kankar)
Khadar	New flood alluvium

Feature	East	West
Nature	Emergent	Submergent
Width	Broad	Narrow
Mouths	Deltas	Estuaries
Harbours	Few	Many

Topic 4: The Northern Plains & Coastal Plains of India

On this page

Conceptual Clarity — Why this Chapter Matters

1. The Great Plains — Overview & Significance

2. Origin of the Great Plains

3. The Four N–S Belts: Bhabar, Tarai, Bhangar, Khadar

4. The Four Meso-Regions of the Northern Plains

5. The Ganga Plain in Detail

6. The Eastern Coastal Plain

7. The Western Coastal Plain & the Rann of Kutch

8. Eastern vs Western Coast: Deltas & Estuaries

9. Economic & Agricultural Significance

10. Problems & GS-I Synthesis

11. Current Affairs & Contemporary Relevance (2024–2026)

11.1 Floods & river management

11.2 Coastal-zone & delta issues

11.3 Why it matters

12. Prelims PYQs (exam-style, high-frequency themes)

13. Mains PYQs + Model Answers

Model Answer

Model Answer

Model Answer

Model Answer

Model Answer

15-Minute Revision Box

Must-Remember Facts — The Northern & Coastal Plains