Unit 2.4: Peninsular Plateau & Hill Ranges (Nilgiri to Rajmahal)
Indian Geography → Indian Geography → PHYSICAL FOUNDATIONS → PHYSICAL FOUNDATIONS → Physiography & Relief | Author: admin | Feb 11, 2026
1. Introduction & Significance Unit 2.4 (Peninsular Plateau & Hill Ranges: Nilgiri to Rajmahal) is essential for UPSC Prelims (MCQs on ranges, hills, plateaus, rivers) and Mains (analytical on Deccan features, minerals, agriculture). SSC/RRB/State PSC ask factuals (Ghats, hills, heights). High weightage in 2026 due to resource questions (minerals in plateau) and disasters (landslides in Western Ghats). Links to current (e.g., Western Ghats biodiversity hotspots, mining regulations). This is a 8–12 mark area — master divisions, Ghats comparison, and hill ranges for Prelims maps and Mains answers on Peninsular relief.
2. Chronological/Geological Timeline
- ~1500–1000 Ma: Peninsular block formed (ancient shield).
- ~65 Ma: Deccan Traps volcanism covers plateau.
- ~50–20 Ma: Western Ghats uplift (rift-related).
- ~30–10 Ma: Eastern Ghats formed (less uplifted).
- Holocene–present: Plateau stable; hill ranges (Nilgiri, Rajmahal) eroded remnants.
- 2020s–2026: Western Ghats conservation (UNESCO hotspot status); recent landslides (2025–2026 reports).
3. Concept Deep Dive Peninsular Plateau: Ancient stable landmass (Gondwana shield); triangular, average 600–900 m height; divided into Central Highlands (north) and Deccan Plateau (south).
- Western Ghats: Continuous, higher (900–1,600 m), steep west slope; Sahyadri; blocks SW monsoon (rain shadow east).
- Eastern Ghats: Discontinuous, lower (600 m), irregular; broken by rivers.
- Hill Ranges: Nilgiri (junction of Ghats), Anaimalai/Palani (south), Rajmahal (northeast edge). Plateau features black soil, lava flows, rivers (Godavari, Krishna). (Ref: NCERT Class 11 India Physical Environment Ch. 2 "Physiography"; Savindra Singh Ch. 8 "Peninsular Plateau"; Goh Cheng Leong Ch. on Plateaus; Majid Husain Ch. 2 for Ghats; Oxford Atlas for relief maps).
4. Key Terminology Box
- Peninsular Plateau: Ancient stable landmass in south India.
- Western Ghats: Continuous western edge; Sahyadri; rain shadow creator.
- Eastern Ghats: Discontinuous eastern edge; lower, broken.
- Deccan Traps: Basaltic lava flows covering plateau.
- Black Soil: Regur; from basalt weathering; cotton-friendly.
- Nilgiri Hills: Junction of Western & Eastern Ghats.
- Rajmahal Hills: Northeastern plateau edge; basalt outlier.
- Sahyadri: Alternate name for Western Ghats.
5. Important Factual Details
| Feature / Range | Location / States | Average Height (m) | Key Characteristics / Features |
|---|---|---|---|
| Peninsular Plateau | South of Narmada | 600–900 | Ancient shield, Deccan Traps, black soil |
| Western Ghats (Sahyadri) | Maharashtra to Kerala | 900–1,600 | Continuous, steep, monsoon barrier |
| Eastern Ghats | Odisha to TN | 600 | Discontinuous, lower, river gaps |
| Nilgiri Hills | Tamil Nadu, Kerala | 2,000+ | Junction of Ghats; Dodabetta (2,637 m) |
| Rajmahal Hills | Jharkhand | 200–600 | Northeastern edge; basalt outlier |
| Anaimalai Hills | Kerala-TN border | 2,000+ | Anamudi (2,695 m, highest south) |
6. Frequently Asked Exam Facts
- Peninsular Plateau: Oldest landmass in India.
- Western Ghats: Higher, continuous, UNESCO hotspot.
- Eastern Ghats: Lower, discontinuous.
- Nilgiri: Junction of Western & Eastern Ghats.
- Anaimalai: Highest peak in south (Anamudi 2,695 m).
- Rajmahal Hills: Northeastern plateau outlier.
- Deccan Traps: Basaltic lava, black soil origin.
- Western Ghats: Blocks SW monsoon (rain shadow).
- Plateau rivers: East-flowing (Godavari, Krishna).
- Black soil: Regur, cotton-rich.
7. Comparison Charts/Tables
| Aspect | Western Ghats | Eastern Ghats |
|---|---|---|
| Height | Higher (900–1,600 m) | Lower (600 m) |
| Continuity | Continuous | Discontinuous |
| Slope | Steep west slope | Gentle east slope |
| Monsoon Impact | Blocks SW monsoon (rain shadow east) | Less blocking |
| Rivers | Short west-flowing | Long east-flowing (Godavari, Krishna) |
8. Spatial Context
- Peninsular Plateau: South of Narmada; Maharashtra (Deccan), Karnataka, Telangana, AP, TN, MP, Odisha.
- Western Ghats: Maharashtra (Sahyadri), Karnataka (Malnad), Kerala (Cardamom Hills), TN (Nilgiri, Palani).
- Eastern Ghats: Odisha (Mahanadi basin), AP (Godavari-Krishna), TN (Javadi, Shevaroy).
- Nilgiri: TN-Kerala border (Ooty, Coonoor).
- Rajmahal: Jharkhand (Santhal Parganas).
- Salem/TN relevance: Salem district on eastern plateau edge; Eastern Ghats nearby (Shevaroy Hills); black/red soil mix; local agriculture (mango, tapioca). Image credit: Wikimedia Commons (CC-BY-SA 4.0) via search, showing map of Peninsular India with Western and Eastern Ghats labeled. Image credit: Wikimedia Commons (Public Domain) via search, showing relief map of Deccan Plateau and hill ranges including Nilgiri and Rajmahal.
9. Flowchart Summary Ancient Shield ? Deccan Volcanism (~65 Ma) ? Plateau Formation ? Western Ghats Uplift (steep, high) ? Eastern Ghats (lower, broken) ? Hill Ranges: Nilgiri (junction), Anaimalai (south), Rajmahal (northeast). Image credit: Wikimedia Commons (CC-BY-SA 4.0) via search, showing diagram of Peninsular Plateau with Ghats and hill ranges cross-section.
10. Ultra-Short Exam Capsule
- Peninsular Plateau: Old shield, Deccan Traps.
- Western Ghats: High, continuous, Sahyadri.
- Eastern Ghats: Low, discontinuous.
- Nilgiri: Ghats junction (TN).
- Anaimalai: Highest south (Anamudi).
- Rajmahal: Northeast outlier.
- Black soil: Plateau feature.
TYPE 2: QUICK REVISION & EXAM TRICKS
1. Highlights & Tricky Points
- Key: Western higher/continuous; Eastern lower/broken.
- Trap: "Highest in south" — Anaimalai (Anamudi); Nilgiri is junction, not highest.
- Trap: "Rajmahal in Himalayas?" — No; Peninsular outlier.
- Trap: Confuse Ghats with Himalayas (Ghats older, stable).
2. Memory Aids/Mnemonics
- Ghats: "West High Continuous, East Low Broken" ? "WHC ELB".
- Hills: "Nilgiri Anaimalai Rajmahal" ? "NAR: Nilgiri Anaimalai Rajmahal".
- Plateau features: "Deccan Traps Black Soil" ? "DTBS" (Deccan Traps Black Soil).
3. Confusing Concepts
- Western vs Eastern Ghats: Western = continuous, high, rain shadow; Eastern = broken, low, river gaps.
- Western: Sahyadri; Eastern: irregular.
- Plateau vs Himalayas: Plateau = stable, old; Himalayas = young, unstable.
TYPE 3: PYQs & EXPECTED QUESTIONS
1. PYQ Vault
- UPSC Prelims 2013: The Western Ghats are also known as? ? Sahyadri.
- SSC CGL 2016: Anamudi is the highest peak in? ? Western Ghats.
- UPSC Prelims 2018: The Nilgiri Hills are located at the junction of? ? Western and Eastern Ghats.
- RRB NTPC 2019: The Rajmahal Hills are part of? ? Peninsular Plateau.
- SSC CGL 2021: The Deccan Plateau is made up of? ? Basaltic lava.
- State PSC (TNPSC 2020): Which hill range is in Tamil Nadu? ? Nilgiri.
- SSC CGL 2019: The Eastern Ghats are? ? Discontinuous.
- RRB JE 2022: Anaimalai Hills are in? ? Tamil Nadu-Kerala border.
- BPSC 2021: The Peninsular Plateau is bounded by? ? Western and Eastern Ghats.
- TNPSC 2022: The plateau soil from basalt is? ? Black soil.
2. 2026 Expected Questions
- Name the two main Ghats of the Peninsular Plateau and their differences.
- Where are the Nilgiri Hills located and what is their significance?
- What is the highest peak in the southern Western Ghats?
- Describe the Rajmahal Hills and their location.
- How do the Western Ghats influence India's monsoon?
- Which features distinguish the Peninsular Plateau from the Northern Plains?