Topic 5: The Peninsular Plateau, Deserts & Islands of India
South of the Great Plains lies the Peninsular Plateau — India's oldest, most stable landmass, a triangular tableland of Archaean rock tilted eastward. This chapter covers its relict ranges (Aravalli, Vindhya, Satpura), the Central Highlands and Deccan Plateau, the flanking Western (Sahyadri) and Eastern Ghats, and the North-Eastern (Meghalaya) plateau. It then adds the two deserts — the hot Thar and the cold desert of Ladakh–Spiti — and India's island groups, the volcanic-tectonic Andaman & Nicobar and the coral Lakshadweep. With labelled diagrams, tables and PYQs + full model answers.
On this page
- 1.The Peninsular Plateau — Overview & Character
- 2.Relict Ranges: Aravalli, Vindhya, Satpura
- 3.The Central Highlands
- 4.The Deccan Plateau
- 5.The Western Ghats (Sahyadri)
- 6.The Eastern Ghats & a Ghats Comparison
- 7.The North-Eastern (Meghalaya) Plateau
- 8.The Deserts: Thar & the Cold Desert
- 9.The Islands: Andaman-Nicobar & Lakshadweep
- 10.Significance & 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 plateau is a Prelims goldmine of ranges, ghats, peaks and passes — and a Mains source on relief, minerals and biodiversity. Sort your prep three ways:
- Definitional / static: the plateau is India's oldest rigid shield, tilted east (so most rivers flow east); the relict ranges (Aravalli = oldest fold mountains; Vindhya-Satpura block the north–south flow); Western vs Eastern Ghats; highest peaks (Anai Mudi in the WG, Mahendragiri in the EG); Deccan Trap.
- Statement-elimination: "Western Ghats are continuous & higher; Eastern Ghats discontinuous & dissected", passes (Thal Ghat, Bhor Ghat, Pal Ghat), Thar in Rajasthan vs Cold Desert in Ladakh, Barren Island = India's only active volcano, coral Lakshadweep vs tectonic Andaman.
- Applied / synthesis (Mains GS-I & GS-III): why the plateau holds India's minerals, why the Western Ghats are a biodiversity hotspot (orographic rain, endemism), the ecological fragility of the Ghats and islands. Needs idea + example + judgement.
Territorial note: the Andaman & Nicobar and Lakshadweep islands and the entire Peninsular landmass are sovereign Indian territory; the cold desert of Ladakh is Indian. The LoC and LAC are not settled international borders.
1. The Peninsular Plateau — Overview & Character
The Peninsular Plateau is a roughly triangular tableland south of the Great Plains — India's oldest and most stable physiographic unit, a fragment of the ancient Gondwana shield made largely of Archaean gneisses and Deccan-Trap basalt.
- Age & stability: a rigid craton (>2.5 Ba), largely aseismic except along reactivated rifts (Narmada–Tapi, Latur, Koyna).
- Shape & tilt: triangular, apex at Kanniyakumari; tilted gently eastward — hence most large peninsular rivers (Mahanadi, Godavari, Krishna, Kaveri) flow east to the Bay of Bengal.
- Exceptions: Narmada & Tapi flow west through rift valleys into the Arabian Sea.
- Relief: average height ~600–900 m; residual (relict) mountains, block-faulted rift valleys, and step-like Deccan-Trap plateaus.
| Attribute | Peninsular Plateau |
|---|---|
| Age | Oldest (Archaean shield), part of Gondwana |
| Stability | Rigid, largely aseismic (rift exceptions) |
| Tilt | Eastward → most rivers flow east |
| Rocks | Gneiss/granite + Deccan-Trap basalt |
| Economic role | India's mineral storehouse |
2. Relict Ranges: Aravalli, Vindhya & Satpura
The plateau's mountains are relict (residual) — the worn-down stumps of once-lofty fold mountains, not young ranges like the Himalaya.
2.1 The Aravalli Range
- One of the oldest fold mountains on Earth (Pre-Cambrian), running NE–SW from Delhi through Rajasthan to Gujarat (~800 km).
- Highly eroded; highest peak Guru Shikhar (Mt Abu, ~1,722 m).
- Acts as a partial barrier checking the eastward spread of the Thar desert.
2.2 The Vindhya & Satpura Ranges
- Vindhya Range: block mountains along the northern edge of the Narmada valley; a traditional divide between North and South India (part of the "Vindhyachal" cultural boundary).
- Satpura Range: a series of block mountains between the Narmada (north) and Tapi (south) rift valleys; highest peak Dhupgarh (Pachmarhi, ~1,350 m); Mahadeo & Maikal hills are parts of it.
- The Narmada–Son and Tapi flow through rift (block-faulted) valleys between these ranges.
| Range | Trend | Highest peak | Note |
|---|---|---|---|
| Aravalli | NE–SW | Guru Shikhar (~1,722 m) | Among oldest fold mts; Thar barrier |
| Vindhya | E–W | ~ (Sadbhawna/Amarkantak area) | N–S cultural divide; N of Narmada |
| Satpura | E–W | Dhupgarh (~1,350 m) | Between Narmada & Tapi rifts |
3. The Central Highlands
North of the Narmada, between the Aravalli and the Vindhya, lie the Central Highlands — a set of plateaus and hill blocks sloping north toward the Ganga plain.
| Sub-region | Location | Signature |
|---|---|---|
| Malwa Plateau | MP–Rajasthan | Deccan-lava & alluvial cover; Chambal, Betwa rise here |
| Bundelkhand | UP–MP | Old granite/gneiss upland; ravines, semi-arid |
| Baghelkhand | MP | Limestone & sandstone; between Son & Narmada |
| Chotanagpur Plateau | Jharkhand–Chhattisgarh–Odisha | India's mineral heartland ("Ruhr of India"); Damodar coalfields |
The Chambal badlands (ravines) on the Malwa edge and the mineral wealth of Chotanagpur are the two most exam-relevant features of the Central Highlands.
4. The Deccan Plateau
South of the Narmada–Satpura belt spreads the great Deccan Plateau — the largest part of the peninsula, bounded by the Western Ghats (west), Eastern Ghats (east) and Satpura–Vindhya (north).
- Maharashtra (Deccan Trap) plateau: vast horizontal basalt sheets → the step-like "trap" topography and black regur soil.
- Karnataka Plateau (Malnad & Maidan): Malnad = hilly, forested west; Maidan = rolling, granitic east.
- Telangana Plateau: Archaean gneiss; drained by the Godavari & Krishna.
- Chhattisgarh Basin: a saucer-shaped lowland on the plateau's north-east, drained by the Mahanadi.
| Deccan sub-unit | Rock/soil | Note |
|---|---|---|
| Maharashtra Plateau | Deccan-Trap basalt → regur | Cotton belt; step topography |
| Karnataka Plateau | Granite/gneiss | Malnad (forested) vs Maidan (open) |
| Telangana Plateau | Gneiss | Godavari–Krishna drainage |
| Chhattisgarh Basin | Sedimentary | Mahanadi; "rice bowl" |
5. The Western Ghats (Sahyadri)
The Western Ghats (Sahyadri) run ~1,600 km along the western edge of the Deccan, from the Tapi valley (Gujarat–Maharashtra) to Kanniyakumari — higher, continuous and far more ecologically significant than the Eastern Ghats.
- Continuity & height: nearly continuous, average ~900–1,600 m, rising southward; a steep west face (escarpment) and gentle east slope.
- Peaks (N→S): Kalsubai (Maharashtra), Doddabetta (Nilgiris), Anai Mudi (Anamalai, ~2,695 m — highest peak in the Western Ghats & in South India), Mullayanagiri (Karnataka).
- Passes (gaps): Thal Ghat (Mumbai–Nashik), Bhor Ghat (Mumbai–Pune), Pal Ghat (Palakkad gap, the largest — Kerala–TN), Sen Kottah.
- Hill clusters: Nilgiri, Anamalai, Cardamom (Elamalai) hills; the Nilgiris link the Western & Eastern Ghats.
- Ecology: a UNESCO World Heritage site & a global biodiversity hotspot — high endemism, orographic rainfall, source of most peninsular rivers.
| Feature | Detail |
|---|---|
| Highest peak | Anai Mudi (~2,695 m), Anamalai hills |
| Major gap | Palakkad (Pal) Gap — largest, Kerala–TN |
| Nilgiri high point | Doddabetta (~2,637 m) |
| Status | UNESCO WHS; biodiversity hotspot |
| Rivers rising here | Godavari, Krishna, Kaveri (flow east) |
6. The Eastern Ghats & a Ghats Comparison
The Eastern Ghats run along the eastern edge of the Deccan, roughly parallel to the Bay of Bengal — but unlike the Western Ghats they are lower, discontinuous and heavily dissected by the east-flowing rivers.
- Character: broken into detached hill ranges (not a continuous wall); average ~600 m.
- Highest peaks: Jindhagada (Andhra–Odisha, ~1,690 m, highest of the EG); Mahendragiri (Odisha); Arma Konda.
- Dissection: cut through by the Mahanadi, Godavari, Krishna & Kaveri as they cross to the coast.
- Junction: the Eastern & Western Ghats meet in the Nilgiri Hills in the south.
| Feature | Western Ghats | Eastern Ghats |
|---|---|---|
| Continuity | Continuous, unbroken | Discontinuous, dissected |
| Height | Higher (~900–2,695 m) | Lower (~600 m) |
| Highest peak | Anai Mudi (~2,695 m) | Jindhagada (~1,690 m) |
| Rivers | Source of peninsular rivers | Crossed & cut by them |
| Rainfall/ecology | Heavy orographic; hotspot | Drier; less endemism |
| Names | Sahyadri | Various local hill names |
7. The North-Eastern (Meghalaya) Plateau
A detached north-eastern extension of the peninsular block — the Meghalaya (Shillong) Plateau — was separated from the main plateau by the Malda gap (a faulted trough now buried under Ganga–Brahmaputra alluvium).
- Sub-divisions (W→E): Garo Hills, Khasi–Jaintia Hills; plus the Mikir (Karbi Anglong) Hills to the east.
- Highest point: Shillong Peak (~1,960 m).
- Rainfall: the southern slopes host Mawsynram & Cherrapunji (Sohra) — among the wettest places on Earth (funnel-shaped valleys trap the monsoon).
- Minerals: coal, limestone, sillimanite & uranium occurrences.
8. The Deserts: Thar & the Cold Desert
India has two contrasting deserts — the hot sandy Thar in the north-west and the high, cold, arid Cold Desert of the trans-Himalaya.
8.1 The Thar (Great Indian) Desert
- Lies west of the Aravalli, mainly in Rajasthan (extending into Gujarat, Punjab, Haryana); hot, arid, <150 mm rain.
- Landforms: shifting sand dunes (barchans), playas (salt lakes like Sambhar), and the intermittent Luni river (the only notable river, draining to the Rann).
- Why dry: the SW monsoon's Arabian-Sea branch runs parallel to the Aravalli and gets little uplift; no orographic barrier faces it.
8.2 The Cold Desert (Ladakh & Spiti)
- Lies in the rain-shadow north of the Great Himalaya — Ladakh, Lahaul–Spiti (HP) — a high-altitude cold desert (Indian territory).
- Extremely cold, arid; sparse vegetation; features glaciers, moraines and the Indus & its tributaries.
- Home to the Hemis high-altitude national park (snow leopard) and the Changthang plateau (Pangong, Tso Moriri).
| Feature | Thar (hot desert) | Cold desert |
|---|---|---|
| Location | Rajasthan (NW), W of Aravalli | Ladakh, Spiti (trans-Himalaya) |
| Cause | Monsoon runs parallel; no uplift | Rain-shadow of Great Himalaya |
| Temperature | Very hot summers | Very cold; freezing |
| Landforms | Dunes, playas (Sambhar), Luni | Glaciers, moraines, high lakes |
9. The Islands: Andaman-Nicobar & Lakshadweep
India has two major island groups, contrasting in origin — the tectonic/volcanic Andaman & Nicobar in the Bay of Bengal and the coral Lakshadweep in the Arabian Sea — plus offshore islands (New Moore, Majuli riverine, etc.). All are sovereign Indian territory.
9.1 Andaman & Nicobar Islands (Bay of Bengal)
- An emerged part of a submarine mountain (extension of the Arakan Yoma–Indonesian arc); tectonic origin.
- Barren Island (Andaman Sea) is India's only active volcano; Narcondam is a dormant volcano.
- Highest point Saddle Peak (North Andaman, ~732 m); Indira Point (Great Nicobar) is India's southernmost point.
- Ten Degree Channel separates the Andamans (north) from the Nicobars (south).
- Dense equatorial forest; tribal reserves (Sentinelese, Jarawa); Great Nicobar biosphere reserve.
9.2 Lakshadweep Islands (Arabian Sea)
- Coral origin — atolls, reefs and coral banks built on submarine volcanic bases; India's only coral islands.
- Small, low-lying (max a few metres); Minicoy is the largest; Kavaratti is the capital.
- The Nine Degree Channel separates Minicoy from the main Lakshadweep group; the Eight Degree Channel separates Minicoy from the Maldives.
- Highly vulnerable to sea-level rise & coral bleaching.
| Feature | Andaman & Nicobar | Lakshadweep |
|---|---|---|
| Sea | Bay of Bengal | Arabian Sea |
| Origin | Tectonic/volcanic | Coral (atolls) |
| Relief | Hilly (Saddle Peak ~732 m) | Low, flat (a few m) |
| Volcano | Barren (active), Narcondam (dormant) | None |
| Key channels | Ten Degree Channel | Nine & Eight Degree Channels |
| Southernmost pt | Indira Point (Gt Nicobar) | — |
10. Significance & GS-I Synthesis
The plateau, deserts and islands together explain much of India's resource base and ecology — a rich source of "significance and fragility" answers.
- Minerals: the ancient Peninsular shield holds the bulk of India's coal, iron, manganese, bauxite & mica (Chotanagpur "Ruhr of India").
- Soils & agriculture: Deccan-Trap regur underpins cotton; plateau red soils and the Chhattisgarh "rice bowl".
- Water & power: the plateau edge (Ghats) gives waterfalls & hydro sites; peninsular rivers rise in the Western Ghats.
- Biodiversity: the Western Ghats are a global hotspot & UNESCO WHS; the islands host endemic & coral ecosystems.
- Fragility: Ghat ecology (Gadgil/Kasturirangan debate), desert expansion, coral bleaching & island sea-level risk demand conservation.
11. Current Affairs & Contemporary Relevance (2024–2026)
The plateau, Ghats, deserts and islands stay "current" through biodiversity policy, critical-mineral pushes, island development and coral/desert stress — verify the latest status. check for latest update or data
11.1 Western Ghats ecology
11.2 Minerals & the plateau
11.3 Islands & deserts
11.4 Why it matters
| Development | Why it matters for UPSC |
|---|---|
| Western Ghats ESA / Wayanad landslides | Ghat fragility & disaster link (GS-I & GS-III). |
| Critical Mineral Mission | Peninsular shield → strategic-resource security. |
| Great Nicobar project | Island development vs tribal/ecology (GS-III). |
| Desert solar parks | Thar → renewable-energy frontier. |
Recurring exam hooks:
- WG vs EG comparison · highest peaks & passes · Aravalli/Vindhya/Satpura (evergreen Prelims).
- Western Ghats ecology & conservation (evergreen Mains GS-I/GS-III).
- Barren Island volcano · coral Lakshadweep · Thar vs Cold Desert (favourite factual sets).
12. Prelims PYQs (exam-style, high-frequency themes)
Objective questions anchored to genuinely tested UPSC themes on India's plateau, Ghats, deserts and islands. Each carries a worked rationale.
Q: The highest peak of the Western Ghats (and of South India) is:
Answer: (a) Anai Mudi (~2,695 m) in the Anamalai hills is the highest peak of the Western Ghats and of peninsular/South India. Doddabetta (~2,637 m) is the Nilgiri high point.
Q: The largest gap (pass) in the Western Ghats, linking Kerala and Tamil Nadu, is the:
Answer: (c) The Palakkad Gap is the largest break in the Western Ghats, carrying the Kochi–Coimbatore road/rail. Thal & Bhor Ghats serve Mumbai–Nashik and Mumbai–Pune.
Q: Which range is regarded as one of the oldest fold mountains in the world?
Answer: (a) Aravalli — Pre-Cambrian, among the oldest fold mountains on Earth; highest peak Guru Shikhar (Mt Abu). Vindhya & Satpura are block mountains bounding rift valleys.
Q: India's only active volcano is located on:
Answer: (b) Barren Island (Andaman Sea) hosts India's only active volcano; Narcondam is dormant. Both are in the Andaman group.
Q: Consider the following about the two Indian island groups:
1. The Andaman & Nicobar Islands are of coral origin.
2. The Lakshadweep Islands are of coral origin.
3. Barren Island lies in the Lakshadweep group.
Which is/are correct?
Answer: (a) 2 only. Andaman & Nicobar are tectonic/volcanic (not coral); Lakshadweep is coral; Barren Island is in the Andaman group, not Lakshadweep.
Q: Which of the following correctly describes the Eastern Ghats relative to the Western Ghats?
Answer: (b) The Eastern Ghats are lower and discontinuous, cut into detached blocks by the east-flowing rivers; the Western Ghats are higher and continuous. They meet at the Nilgiris.
Q: The Thar Desert's aridity is chiefly because:
Answer: (a) The Arabian-Sea monsoon branch runs roughly parallel to the Aravalli, so there is no barrier to force uplift and rain. (The Cold Desert, by contrast, is a Himalayan rain-shadow.)
Q: The Chotanagpur Plateau is often called the "Ruhr of India" because it:
Answer: (b) Its Damodar coalfields plus iron, mica, bauxite and copper made it India's mineral & heavy-industry heartland — hence the "Ruhr of India" tag.
Likely: Anai Mudi/Doddabetta/Jindhagada peaks · Palakkad/Thal/Bhor passes · Aravalli (oldest fold) vs Vindhya-Satpura (block) · WG vs EG contrast · Barren Island active volcano · coral Lakshadweep vs tectonic A&N · Ten/Nine/Eight Degree channels · Indira Point · Thar vs Cold Desert cause · Chotanagpur minerals · Meghalaya rainfall. check for latest update or data
13. Mains PYQs + Model Answers
Genuine UPSC GS-I themes on India's plateau, Ghats, deserts and islands and their resource & ecological significance. Each carries a full answer skeleton — Introduction → body → Conclusion.
Q: The Peninsular Plateau is the storehouse of India's minerals. Examine the geological reasons and the economic consequences.
Model Answer
- Introduction: the peninsula is one of Earth's oldest rigid shields (Archaean–Dharwar), and this antiquity is precisely why it concentrates India's minerals.
- Geological reason: long-consolidated Archaean–Dharwar belts host metallic minerals (iron, manganese, gold, mica), while overlying Gondwana basins hold coal and Deccan basalt yields bauxite & regur.
- Spatial concentration: Chotanagpur ("Ruhr of India"), Karnataka and Telangana plateaus form the mining core; the Damodar valley anchors coal & steel.
- Economic consequence: this endowment underpins India's steel, power & heavy industry, but also raises mining-vs-tribal-rights and environmental questions.
- Conclusion: the plateau's ancient rock is the silent foundation of India's industrial economy — making its sustainable, equitable mining a strategic priority.
Q: Compare the Western and Eastern Ghats, and explain why the Western Ghats are ecologically more significant.
Model Answer
- Introduction: the two Ghats flank the Deccan but differ sharply — a contrast that explains their unequal ecological importance.
- Physical contrast: the Western Ghats are continuous, higher (Anai Mudi ~2,695 m) with a steep west face; the Eastern Ghats are low, broken and dissected by east-flowing rivers.
- Why WG matters more: their unbroken height forces heavy orographic rainfall, feeds most peninsular rivers, and sustains high endemism — a UNESCO WHS & global biodiversity hotspot.
- Fragility: deforestation, mining & construction trigger landslides (Wayanad); the Gadgil/Kasturirangan reports seek eco-sensitive zoning.
- Conclusion: continuity and height make the Western Ghats India's ecological spine — protecting them is central to water, biodiversity and disaster resilience.
Q: Account for the aridity of the Thar Desert and contrast it with the cold desert of Ladakh.
Model Answer
- Introduction: India's two deserts — the hot Thar and the cold Ladakh–Spiti desert — are arid for opposite reasons.
- Thar aridity: the Arabian-Sea monsoon runs roughly parallel to the Aravalli, so there is no orographic barrier to force uplift; descending, dry air keeps rainfall below ~150 mm.
- Cold desert: Ladakh lies in the rain-shadow north of the Great Himalaya, which blocks the monsoon; extreme altitude adds intense cold.
- Contrast: Thar = hot, sandy, dunes & playas (Sambhar), Luni river; Cold Desert = freezing, high, glaciated, Indus-drained — yet both are sparsely vegetated Indian territory.
- Conclusion: orographic geometry (parallel monsoon vs rain-shadow) explains both deserts — a neat demonstration of relief controlling climate.
Q: Discuss the strategic and ecological significance of India's island territories.
Model Answer
- Introduction: the Andaman & Nicobar (Bay of Bengal) and Lakshadweep (Arabian Sea) extend India's reach far into the Indian Ocean.
- Strategic value: A&N hosts India's only tri-services command and overlooks the Malacca approaches; the islands vastly enlarge India's EEZ and maritime domain awareness.
- Ecological value: A&N holds equatorial forests, endemic species & vulnerable tribes; Lakshadweep's coral atolls are biodiversity-rich but climate-fragile.
- Tensions: projects like Great Nicobar and rising tourism clash with tribal rights, coral health and sea-level risk — needing careful zoning.
- Conclusion: the islands are both a strategic frontier and an ecological trust — security and sustainability must advance together.
Q: Explain how the eastward tilt of the Peninsular Plateau has shaped its drainage.
Model Answer
- Introduction: the plateau is tilted gently eastward, a structural fact that governs where its rivers flow.
- Consequence: the major rivers — Mahanadi, Godavari, Krishna, Kaveri — rise in the Western Ghats and flow east across the Deccan to the Bay of Bengal, building deltas.
- Exceptions: the Narmada & Tapi flow west through rift valleys to the Arabian Sea, forming estuaries, not deltas.
- Conclusion: a single tilt explains the east-flowing, delta-forming pattern of peninsular drainage — and its two rift-valley exceptions.
Likely: plateau as mineral storehouse · WG vs EG & Ghat ecology/conservation · Thar vs Cold Desert causation · island strategic-ecological significance · eastward tilt & drainage · Deccan Trap soils & relief. check for latest update or data
15-Minute Revision Box
Must-Remember Facts — Plateau, Deserts & Islands
- Oldest, most stable; triangular; tilts east → rivers flow east
- Narmada & Tapi = west-flowing rift valleys
- Aravalli = oldest fold mts; Guru Shikhar (Mt Abu)
- Vindhya & Satpura = block mts around Narmada–Tapi
- Chotanagpur = "Ruhr of India" (Damodar coal)
- WG = continuous, high; Anai Mudi (~2,695 m) highest
- Passes: Thal, Bhor, Palakkad (largest)
- EG = low, broken; Jindhagada highest; meet at Nilgiris
- WG = UNESCO WHS & biodiversity hotspot
- Thar = Rajasthan; monsoon parallel to Aravalli; Luni, Sambhar
- Cold Desert = Ladakh–Spiti; Himalayan rain-shadow
- A&N = tectonic/volcanic; Barren = only active volcano
- Saddle Peak highest; Indira Point southernmost; Ten Degree Channel
- Lakshadweep = coral; Minicoy largest; Nine/Eight Degree Channels
- Meghalaya plateau → Mawsynram/Cherrapunji wettest