• The Deccan plateau is a major landmass in India and is considered one of its physiographic divisions.
• It is located between the Western Ghats to the west and the Eastern Ghats to the east.
• The Western Ghats are a continuous range of mountains known as Sahyadri.
• The Eastern Ghats consist of discontinuous mountain ranges.

Western Ghats (or The Sahyadris)

• The Western Ghats were formed by the subduction of the Arabian basin and tilting of the peninsula during Himalayan uplift.
• The Western Ghats have a block mountain look in the west and appear as escarpments and stairway formations.
• The Western Ghats look like Treppen along the west coast.
• The eastern section of the Western Ghats is a rolling plateau with a low slope that gradually merges with the sudden plateau.
• The Western Ghats is one of the eight hotspots of biological diversity in the world and spreads across six states – Gujarat, Maharashtra, Goa, Karnataka, Tamil Nadu, and Kerala.
• It is a UNESCO World Heritage site and is older than the Himalayas.
• The Western Ghats impact Indian monsoon weather patterns by intercepting the rain-laden monsoon winds from the south-west during late summer.
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• It stretches from Tapi valley to Kanyakumari.
• It is called Sahyadri till 11° N.
• It has three sections.
  • Northern Western Ghats
  • Middle Sahyadri(Central Western Ghats)
  • Southern Western Ghats

Northern Western Ghats

• The Northern Western Ghats are located between the Tapi valley and 16° N lat.
• It is covered with basaltic lava and is highly rugged and dissected by rivers.
• The highest point in this area is Kalsubai.
• The northern section of the Western Ghats from Tapi valley to a little north of Goa is made of horizontal sheets of Deccan lavas (Deccan Traps).
• The average height of this section of the Ghats is 1,200 m above mean sea level, with some peaks reaching higher.
• Important peaks in this area include Kalasubai (1,646 m), Salher (1,567 m), Mahabaleshwar (1,438 m), and Harishchandragarh (1,424 m).
• Thal ghat and Bhor ghat are important passes that provide passage by road and rail between the Konkan Plains in the west and the Deccan Plateau in the east.

The Middle Sahyadri

• The Middle Sahyadri extends from 16°N latitude up to the Nilgiri hills and is made of granites and gneisses.
• Dense forests cover this area, and the western scarp is considerably dissected by headward erosion of the west-flowing streams.
• The average height of this area is 1200 m, and important peaks include Vavul Mala (2,339 m), Kudremukh (1,892 m), Pashpagiri (1,714 m), and Doda Betta (2,637 m) and Makurti (2,554 m) in the Nilgiri Hills.
• The Nilgiri Hills join the Sahyadris near the trijunction of Karnataka, Kerala, and TN and rise abruptly to over 2,000 m, marking the junction of the Western Ghats with the Eastern Ghats.
• The Central Western Ghats, between 16° – 11° N, have a granitic structure, with the highest point in Karnataka being Mulangiri in Baba Budan Hill.
• This section has developed nick points, waterfalls like Gersoppa/Jog Falls over Sharavathi River, and two distinctive features – Malnad, highlands, and Maidan, a plateau surface.
• The river Kaveri emerges from the Brahmagiri Hills, and the lake is called Talkaveri Lake.
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The Southern section

• The southern part of the Western Ghats is called the southern mountain complex and is separated from the main Sahyadri range by Pal ghat Gap (Palakkad Gap).
• Pal ghat Gap is a rift valley and is used by several roads and railway lines to connect the plains of Tamil Nadu with the coastal plain of Kerala.
• Moist-bearing clouds of the southwest monsoon can penetrate inland through this gap and bring rain to the Mysore region.
• South of Pal ghat Gap, there is a system of steep and rugged slopes on both the eastern and western sides of the Ghats.
• Anai Mudi, with a height of 2,695 m, is the highest peak in southern India.
• Three ranges radiate from Anai Mudi: Anaimalai to the north, Palani to the north-east, and the Cardamom Hills or the Ealaimalai to the south.
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• Southern Western Ghats has 3 parallel ranges to the coast namely–
  • Nilgiris
  • Annamalai
  • Cardamon and
  • Transverse range – Palani
• Palghat gap is B/W the southern part of the Western Ghats and the main Sahyadri
• These mountains have an average elevation of 1600 – 2500m.
  • Dodabetta is the highest peak of Nilgiris
  • Anamudi is the highest peak of Annamalai and South India.
  • Agasti malai is the highest peak of Cardamom hills.

Eastern Ghats

• The Eastern Ghats are a chain of broken and detached hills that run parallel to India’s east coast.
• They start from the Mahanadi in Odisha and end at the Vagai in Tamil Nadu.
• The Eastern Ghats lack structural unity and physiographic continuity, and are treated as independent hill groups.
• The northern part of the Eastern Ghats, between the Mahanadi and the Godavari, exhibit true mountain character.
• This area includes the Maliya and the Madugula Konda ranges, with Mahendra Giri (1,501 m) being the tallest peak in the Maliya range.
• Between the Godavari and the Krishna, the Eastern Ghats lose their hilly character and are occupied by Gondwana formations.
• The Eastern Ghats reappear as a continuous hill range in Cuddapah and Kurnool districts of Andhra Pradesh, called the Nallamalai Range, with a general elevation of 600-850 m.
• The southern part of the Nallamalai Range is called the Palkodna range.
• To the south, the hills and plateaus have very low altitudes, with Javadi Hills and Shevroy-Kalrayan Hills being the only distinct features with an elevation of 1,000 m.
• The Biligiri Rangan Hills in Karnataka have a height of 1,279 m.
• The Eastern Ghats merge with the Western Ghats in the southern part.
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• Geologically Precambrian fold mountains, younger than Aravalli
• Highly dissected and fragmented, appearing as hills of denudation along the eastern coast
• Average elevation: 150-300m (very low)
• Made of different rock systems, Khondelite series is major rock system in central AP and Orissa, granitic gneiss in southern TN
• Peninsular rivers have carved out wide U shaped valleys, making these mountains scattered
• Known as Shevaroy Hills and Javadi Hills in TN, Palkonda range, Vellikonda range, and Nalamallai hills in AP
• Northern Circars between Godavari and Mahanadi basin are the highest part of Eastern Ghats
• Mahendragiri in Ganjam District, Orissa is the highest point
• These mountains hardly have any watersheds, thus no rivers except R.Indravati emerge from the Eastern Ghats.

Difference between Western Ghats vs Eastern Ghats

Western Ghats	Eastern Ghats
600 – 1200m, still higher in South	150-300 m
Rock System – Chernochete	Gneiss, Khondalite, Dharwar
Due to tilting, further upliftment	Further subdued
The most important watershed in southern India – all east-flowing rivers emerging	Poor Watershed
Treppen – Like formation, look like block mountains in the west	Ancient fold mountains and presently mountains of denudation
DenselyForested	Less Forested – Mostly dry deciduous to moist deciduous
Laterite Soils found	Red Sandy soil
100cm isohyte is the crest of Western Ghats. It rains 150cm+ all along the west coast	Rainfall 60-100 cm

Significance of the Peninsular Plateau

• The Peninsular Plateau has vast deposits of various minerals like iron, manganese, copper, bauxite, chromium, mica, gold, etc.
• Almost all of India’s Gondwana coal deposits (98%) are found in this plateau.
• The plateau also has large reserves of slate, shale, sandstones, marbles, etc.
• The northwestern plateau has fertile black lava soil that is ideal for growing cotton.
• Some hilly areas in the south are suitable for growing tea, coffee, rubber, etc., while some low-lying areas are good for rice cultivation.
• The highlands of the plateau are covered with diverse forests that offer a wide range of forest products.
• Rivers originating in the Western Ghats provide opportunities for developing hydroelectricity and irrigation facilities for agriculture.
• The plateau is home to several popular hill resorts, such as Ooty, Panchmarhi, Kodaikanal, Mahabaleshwar, Khandala, Matheron, Mount Abu, etc.