The Peninsular Plateau and the Central Highlands

Detail

1. The Peninsular Plateau: shape, height and limits

• Peninsular Plateau: a large raised block of very old, hard rock that makes up most of south and central India. Its shape is an irregular triangle.
• It rises from about 150 m above the river plains to 600-900 m.

• It is one of India's oldest and most stable landmasses. It is part of the ancient Archaean block (rocks formed more than 2.5 billion years ago) that once belonged to the old southern supercontinent Gondwana.

• Outer limits (exam favourite):

Direction	Limit	State
North-west	Delhi ridge (the northern tip of the Aravallis)	Delhi
East	Rajmahal hills	Jharkhand
West	Gir range	Gujarat (Saurashtra)
South	Cardamom hills	Kerala–Tamil Nadu
North-east extension	Shillong and Karbi Anglong plateaus	Meghalaya, Assam

• Delhi ridge: the low, rocky northern end of the Aravalli range. It runs into Delhi and is the north-western limit of the plateau.
• North-east extension: the Meghalaya (Shillong) plateau and Karbi Anglong belong to the same old block. They are cut off from the main plateau by the Malda gap (a fault-made low area between the Rajmahal hills and the Meghalaya plateau, later filled with river silt).

2. Slope and what the rivers show

• General slope: west to east.
• The Western Ghats edge is high; the land falls gently towards the Bay of Bengal.

• So the big Peninsular rivers — Mahanadi, Godavari, Krishna, Kaveri — flow east and form deltas.

• Exceptions: the Narmada and Tapi flow west into the Arabian Sea. They flow through rift valleys (see below), not down the general slope. They make estuaries, not deltas.

• North of the Narmada (Central Highlands), the slope is to the north and north-east. So the Chambal, Betwa, Ken and Son flow north or north-east to the Yamuna and Ganga.

3. Patland plateaus

• Patland plateau: a plateau made of flat-topped, step-like surfaces at different heights. Long erosion has worn the land down to level tops; each "step" is a separate plateau surface.
• Examples: Hazaribagh, Palamu, Ranchi (Jharkhand), Malwa (Madhya Pradesh), Coimbatore (Tamil Nadu) and the Karnataka plateau.
• In the Chotanagpur region the flat tops are locally called pats (e.g. Netarhat pat).

4. Landforms of the plateau

Landform	Simple meaning	How it forms
Tor	A pile of rounded rock blocks standing on bare rock	Granite weathers along its cracks → soft parts wash away → hard rounded blocks are left standing
Block mountain	A block of land raised up between two faults	Earth's crust breaks (faults) → one block is pushed up or the sides sink
Rift valley	A long, narrow valley that has sunk between two parallel faults	Crust stretches and breaks → the middle block drops down. Examples: Narmada, Tapi, Damodar
Spur	A ridge sticking out from a hill side	Rivers cut valleys on both sides of a ridge
Hummocky hill	Low, rounded, uneven hills	Long weathering and erosion of old rock
Bare rocky structure	Exposed rock with little soil	Soil removed by erosion
Quartzite dyke	A wall-like band of hard rock cutting across other rocks	Molten rock filled a crack and cooled; it resists erosion and stands out like a wall

• Why dykes matter: a dyke works like a natural dam wall. Water collects behind it. So dykes make good natural water-storage sites.
• Soils: the west and north-west of the plateau is covered with black soil (regur). It forms from weathered basalt lava of the Deccan Traps. It holds moisture well and suits cotton.

5. Geological history: an old block that still moves

• The plateau has gone through repeated uplift, sinking (submergence), faulting and fracturing.
• Uplift raised block mountains.
• Faulting made rift valleys (Narmada, Tapi, Damodar).

• Fracturing opened cracks for lava flows and dykes.

• Bhima fault: a fault zone along the Bhima river (a Krishna tributary, Maharashtra–Karnataka). It is still seismically active — earthquakes can happen there. So the "stable" plateau is not fully quake-free.

6. Ravines of the north-west: the Chambal badlands

• Ravine: a deep, narrow gully cut by running water. Badlands: land so cut up by gullies that it cannot be farmed.
• How Chambal ravines form:
• The Chambal and its tributaries flow through soft, loose alluvium (river-laid silt).
• Heavy monsoon rain runs off fast over land with little plant cover.

• Water cuts gullies → gullies deepen and join → a maze of ravines.

• Where: Bhind and Morena (Madhya Pradesh) and Dholpur (Rajasthan).

• Effects: farming is very hard; the land is lost every year as gullies grow. The hidden maze of ravines long sheltered dacoits.

7. The Central Highlands: limits, height and slope

• Central Highlands: the part of the Peninsular Plateau that lies north of the Narmada river. It covers most of the Malwa plateau.
• Boundaries:
• West: the Aravalli range.
• South: the Satpura range, which forms the northern edge of the Deccan.
• East: the Rajmahal hills; to their south lies the Chotanagpur plateau.

• North-west: they continue under the sand to Jaisalmer (Rajasthan), buried by longitudinal dunes (long sand ridges that run along the wind direction) and barchans (crescent-shaped dunes whose horns point downwind).

• Height: 700-1,000 m. Slope: towards the north and north-east.

• Rocks: metamorphic rocks — rocks changed by great heat and pressure — such as marble (from limestone), slate (from shale) and gneiss (from granite).
• Rivers:
• Most Yamuna tributaries rise in the Vindhyan and Kaimur ranges.
• The Banas is the only significant tributary of the Chambal. It rises in the Aravallis (Rajasthan) and joins the Chambal on the Rajasthan side.

8. The Aravalli range

• Age and type: one of the oldest fold mountains in the world, about 2.5 billion years old. Fold mountain: a range made when layers of rock are squeezed and bent upward. Billions of years of erosion have worn it down. It is now a relict range — only the worn-down stump of a once-high mountain.
• Extent: about 700 km south-west to north-east — Gujarat → Rajasthan → Haryana → Delhi (ending as the Delhi ridge).
• Height: most hills are 300-900 m. Highest point: Guru Shikhar, near Mount Abu (Rajasthan), about 1,722 m.
• Role as a barrier: it stops the Thar desert from spreading east into the Ganga plains. The Supreme Court (December 2025) called the Aravallis the "green lungs" of north-western India and the main barrier between the dry north-western desert and the fertile northern plains [2].
• Minerals: marble, granite, zinc, copper.

• Zawar (near Udaipur, Rajasthan): ancient mines show Indians first mastered zinc extraction more than eight centuries ago.

• Heritage: the forts of Chittorgarh, Kumbhalgarh and Ranthambore stand on Aravalli hills.

9. The Aravallis today: mining, Green Wall and the court

• Problem: illegal mining.
• Mining cuts away hills → gaps open in the range.
• Dust-laden winds from the Thar blow through these gaps → more dust storms in Delhi-NCR and the plains.

• Loss of forest also reduces groundwater recharge.

• Aravalli Green Wall Project (launched March 2023, MoEFCC):

• Aim: green a 5 km buffer around the Aravalli range [3].
• Covers 29 districts in four states — Delhi, Haryana, Rajasthan and Gujarat [3].
• A Detailed Action Plan for Aravalli Landscape Restoration (2025) proposes restoring about 6.31 million hectares, with a phased plan for 2025-2034 — forest restoration, grassland revival and mine reclamation, using funds from CAMPA, MGNREGS and the Green India Mission [4].

• The plan links to India's work against land degradation and desertification (land turning dry and unproductive) [4][5].

• Supreme Court and the definition of the Aravallis (status as of 2026):

• The Court has dealt with Aravalli mining since 2002. Each state (Delhi, Rajasthan, Haryana, Gujarat) used a different definition [2].
• 9 May 2024: the Court ordered a committee (MoEFCC, the four states, FSI, GSI, CEC) to frame a uniform definition [2].
• Committee report (3 October 2025):
  • Aravalli Hill: any landform in the Aravalli districts that rises 100 m or more above local relief. Local relief is measured from the lowest contour line around the landform [2].
  • Aravalli Range: two or more such hills within 500 m of each other [2].
  • Rajasthan had used this "100 m above local relief" rule since 9 January 2006. It came from a 2002 committee report based on the Richard Murphy landform classification [6].
• 20 November 2025: the Court accepted this definition. It also stopped new mining leases until a Management Plan for Sustainable Mining (MPSM) for the whole range is prepared by MoEFCC through ICFRE [2][6].
• 29 December 2025 (suo motu case): after public criticism, the Court put the 20 November 2025 judgment and the committee's definition in abeyance (on hold) [2].
  • Concern: only 1,048 of 12,081 hills in Rajasthan were said to meet the 100 m test. Lower hills could lose protection [2].
  • The Court proposed a High-Powered Expert Committee to review the definition [2].
  • Until further orders, no new or renewed mining leases are allowed in the Aravallis as defined in the FSI report of 25 August 2010, without the Court's permission [2].

10. Other units of the Central Highlands and their edges

Unit	Location	Key facts
Malwa plateau	Western Madhya Pradesh	Lava plateau (covered by Deccan basalt); Chambal rises near Mhow (Indore district); black soil → cotton and soybean
Vindhyan range	North of the Narmada, MP	An escarpment (a long, steep cliff-like slope); stands north of the Narmada rift; the traditional divide between north and south India; Betwa and Ken rise here
Satpura range	Between the Narmada (north) and Tapi (south), MP–Maharashtra	Scarped block plateaus, 600-900 m; a relict, highly denuded (worn down), discontinuous range; northern edge of the Deccan; highest point Dhupgarh (~1,350 m) near Pachmarhi
Maikal range	Eastern MP–Chhattisgarh border	Links the Satpura with Chotanagpur; its Amarkantak plateau is the source of the Narmada (flows west) and Son (flows north-east to the Ganga)
Bundelkhand	UP–MP border	Old granite-gneiss upland; drained by the Betwa and Ken towards the Yamuna
Baghelkhand	North-east MP (Rewa area)	Upland east of Bundelkhand, south of the Kaimur hills; drained by the Son system
Gir range	Saurashtra, Gujarat	Western edge of the plateau; last wild home of the Asiatic lion
Rajmahal hills	Jharkhand	Basalt lava hills (Rajmahal traps); the Ganga bends around them; eastern limit of the plateau
Chotanagpur plateau	Jharkhand (into Chhattisgarh, Odisha, West Bengal, Bihar)	Made of the Hazaribagh, Ranchi and Palamu plateaus; India's richest mineral store — coal, iron ore, mica, bauxite; highest peak Parasnath (~1,365 m)

• Vindhya vs Satpura — the Narmada rift:
• The Narmada flows west in a rift valley between the Vindhyas (north) and Satpuras (south).
• The Tapi flows west south of the Satpuras in a parallel trough.

• So the order north → south is: Vindhya → Narmada → Satpura → Tapi.

• Chotanagpur minerals and the Damodar:

• The Damodar flows east through a rift valley in this plateau.
• Old Gondwana rocks in this trough hold India's main coal fields (e.g. Jharia, Bokaro, Raniganj on the West Bengal side).

11. Origins of Central Highland rivers (quick map)

River	Rises in	Flows	Joins
Chambal	Near Mhow, Malwa plateau	North-east through MP, Rajasthan	Yamuna (Uttar Pradesh)
Banas	Aravallis, Rajasthan	East / north-east	Chambal (its only big tributary)
Betwa	Vindhyan range, MP	North-east	Yamuna
Ken	Vindhyan–Kaimur hills, MP	North	Yamuna
Son	Amarkantak (Maikal)	North-east	Ganga (Bihar)
Narmada	Amarkantak (Maikal)	West, in a rift valley	Arabian Sea (Gulf of Khambhat)

Prelims Hooks

• Limits of the Peninsular Plateau: Delhi ridge (NW) – Rajmahal hills (E) – Gir range (W) – Cardamom hills (S); Shillong and Karbi Anglong = north-eastern extensions.
• Slope: Peninsular Plateau slopes west → east; Central Highlands slope north and north-east (so the Chambal, Betwa and Ken flow north to the Yamuna).
• Same source, opposite directions: the Narmada (west) and Son (north-east) both rise at Amarkantak in the Maikal range.
• North → south order: Vindhya → Narmada → Satpura → Tapi.
• Highest points: Guru Shikhar (Aravalli, ~1,722 m) > Parasnath (Chotanagpur, ~1,365 m) > Dhupgarh (Satpura, ~1,350 m).
• Trap: the Banas (rising in the Aravallis) is the Chambal's only significant tributary; the Chambal itself rises near Mhow (Malwa), not in the Aravallis.
• Pats = flat tops of the Chotanagpur patland plateaus (Hazaribagh, Ranchi, Palamu).
• Chambal ravines (badlands) = Bhind and Morena (MP) + Dholpur (Rajasthan); formed by gully erosion of soft alluvium.
• Aravalli Green Wall: 5 km buffer; 29 districts; four states — Delhi, Haryana, Rajasthan, Gujarat [3].
• SC Aravalli definition: a landform 100 m above local relief = Aravalli Hill; hills within 500 m = Range. Accepted on 20 November 2025, kept in abeyance on 29 December 2025 [2].

Mains Points

• Old, stable but not inert (GS-I): the plateau is an Archaean block, yet repeated uplift, faulting and fracturing shaped its rift valleys (Narmada, Tapi, Damodar), block mountains and dykes. The active Bhima fault shows that peninsular India still has earthquake risk. Dam and city planning must allow for this.
• Landforms drive resources (GS-I/III): Deccan basalt → black soil → the Malwa and Maharashtra cotton-soybean belt. Gondwana troughs in Chotanagpur → coal, iron ore, mica and bauxite → steel and power industries. Quartzite dykes give natural dam sites.
• Land degradation in the north-west (GS-III): the Chambal ravines destroy farmland every year through gully erosion. Responses include ravine reclamation, plugging gullies, building check dams and planting trees to hold soil.
• Aravalli protection as a test of governance (GS-III): mining gaps → Thar dust reaches Delhi-NCR → aquifers and forests decline. Responses include the Green Wall (2023) and the 2025 restoration plan for 6.31 million ha [3][4]. The definition dispute (100 m rule; 1,048 of 12,081 Rajasthan hills) shows how one technical measure can decide what nature gets protected. The Court has put the rule on hold pending expert review [2].