UPSC Prelims GS Revision Indian Geography

UPSC Prelims GS Revision Notes Indian Geography

India Size and Location

  • India main land extends between – Latitudes 8°4’N and 37°6’N; Longitudes 68°7’E and 97°25’E.
  • The total size of India is approximately 2.4 per cent of the total size of the world.
  • Tropic of Cancer divides the country into almost two equal parts.
  • In India Tropic of Cancer passes through 8 states. Rajasthan, Gujarat, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram.
  • India is the 7th largest country in the world after Russia ; Canada ; USA ; China ; Brazil ; Australia.
  • India’s total size is approximately 3.28 million square kilometers.
  • The total length of the coastline including two islands is almost 7516.6 kilometers.
  • The east west extent appears smaller than north south extent due to the fact that latitudes are equidistant from each other but distance between longitudes decreases as one moves from equator to poles.
  • The time along Standard Meridian of India (82°30’E) passing through Mirzapur (in Uttar Pradesh) is taken as the standard time for the whole country.
  • India shares its land boundaries with Pakistan and Afghanistan in the northwest, China, Nepal and Bhutan in the north and Myanmar and Bangladesh in the east.
  • The two island countries located to the south of India across the sea are Sri Lanka and Maldives, which serve as our southern neighbors.

Indian Physical Features

Major physiographic divisions of India

  • Himalayan Mountains
  • Northern Plains
  • Peninsula plateau
  • Great Indian desert
  • Coastal plains
  • Islands

Himalayan Mountains

  • Young fold mountains.
  • Run in west-east direction from Indus to Brahmaputra.
  • Arc shape.
  • Height greater in the East.

Himadri / Great / Inner Himalayas

  • Continuous range.
  • Known for Loftiest peaks with an average height of 6,000 metres.
  • Contains all prominent Himalayan peaks.
  • Folds are asymmetrical in nature here.
  • Contains Granite core.

Himachal / Lesser Himalayas

  • Most rugged.
  • Highly compressed and altered rocks found here.
  • Pir Panjal, Dhaula Dhar and Mahabharat ranges found here.
  • Pir Panjal range is the longest.
  • Well known for its hill stations
  • Valley of Kashmir lies here.
  • Kangra and Kullu Valley lies in Himachal Pradesh.
  • Mussoorie, Nainital, Ranikhet lies here.

Shiwaliks / Outer Himalayas

  • Known for Unconsolidated sediments brought down by rivers.
  • Thick gravel and alluvium in valleys
  • Known for Duns – Dehra Dun, Kotli Dun and Patli Dun.

Latitudinal divisions : Divided from west to east – demarcated by river valleys

  • Punjab Himalaya b/w Indus Satluj
  • Kumaon Himalayas b/w Satluj Kali
  • Nepal Himalayas b/w Kali Tista
  • Assam Himalayas b/w Tista Dihang

Puruvachal comprises of following hills from north to South:

  • Patkai hills
  • Naga hills
  • Manipur hill
  • Mizo hills

Northern Plains of India

  • The Northern Plains of India, also known as the Indo-Gangetic Plains, are a vast and fertile region in northern India. This region is formed by the alluvial deposits of the Indus, Ganges, and Brahmaputra rivers, making it one of the most agriculturally productive areas in the country.
  • The region is relatively flat and is characterized by rich alluvial soil, which is ideal for agriculture.

Northern Plains of India can be broadly divided into three parts based on their geographical location and characteristics. These divisions are:

  • Punjab Plains: The Punjab Plains are located in the northwest region of the Northern Plains. They primarily cover the state of Punjab and extend into parts of Haryana. It is formed by Indus and its tributaries.
  • Gangetic Plains: The Gangetic Plains are the central part of the Northern Plains and are named after the Ganges River. This vast plain extends from the western state of Uttarakhand in the foothills of the Himalayas to the eastern state of West Bengal, covering major parts of Uttar Pradesh and Bihar. The Gangetic Plains are known for their alluvial soil and are one of the most fertile regions in the world.
  • Brahmaputra Plains: The Brahmaputra Plains are located in the easternmost part of the Northern Plains, primarily in the state of Assam. This region is formed by the floodplains of the Brahmaputra River and its tributaries. The Brahmaputra Plains are known for their rich biodiversity and extensive tea plantations.

Northern plains can be divided into four regions based on relief features

Bhabar:

  • It is a narrow belt lies parallel to slopes of Shiwaliks.
  • All streams disappear in this bhabar belt.

Terai:

  • It lies south of Bhabar.
  • Streams and rivers re-emerge here and create a wet, swampy and marshy region known as Terai.
  • It is thickly forested region full of wildlife.

Bhangar:

  • It is the older alluvial plain of the Northern Plains.
  • It is elevated above the floodplains and consists of older alluvial deposits.
  • It presents a terracelike feature.
  • Here Soil contains calcareous deposites kankar.

Khadar:

  • It is the younger alluvial plain formed by the deposition of new alluvium brought by rivers during floods.
  • It is fertile and ideal for intensive agriculture.

Peninsular Plateau

  • It is a vast, triangular plateau located in the southern part of India.
  • It composed of old crystalline, igneous and metamorphic rocks.
  • The Western Ghats and the Eastern Ghats flank the plateau on the west and east respectively.
  • The Deccan Plateau is the largest section of the Peninsular Plateau.

Peninsular plateau consists of two broad divisions

Central Highlands:

  • It lies to the north of the Narmada river.
  • It includes regions like the Malwa Plateau, Bundelkhand, Chota Nagpur Plateau, and Vindhya Range.
  • It is wider in the west and narrows in the east.
  • Chambal, Sind, Betwa, Ken rivers flows from southwest to northeast here.

Deccan Plateau:

  • It is a triangular landmass lies south of Narmada.
  • It is higher in the west and slopes gently eastwards.
  • It composed of ancient volcanic lava flows.
  • Here the flat-topped hills known as “Dhars.”
  • It includes regions like the Deccan Trap, Western Ghats, Eastern Ghats, and the Nilgiri Hills.
  • Its Deccan Trap region known for black soil, which is suitable for cotton cultivation.

Western Ghats

  • Also known as the Sahyadri Mountain Range.
  • It is a UNESCO World Heritage Site located along the western coast of India.
  • It runs parallel to the Arabian Sea.
  • It is a continuous range and crossed through passes only.
  • Thal, Bhor, Pal Ghats are well known passes.
  • Western Ghats are higher than Eastern Ghats.
  • Height of Western Ghats increases from north to south.
  • Kodaikanal on Palani hills is eastward extension of Western Ghats.

Eastern Ghats

  • These are discontinuous range and located along the eastern coast of India.
  • They run parallel to the Bay of Bengal.
  • Dissected by rivers draining into Bay of Bengal.
  • Mahanadi, Godavari, Krishna, and Pennar are prominent rivers.
  • Shevroy and Javed hills are lies in the southeast.
  • Jindhagada Peak is the tallest peak of Eastern Ghats.

Great Indian Desert

  • It is also known as the Thar Desert.
  • It is a vast arid region located in northwestern India.
  • It lies west of Aravali Hills.
  • Here rivers are ephemeral.
  • Luni is the only large river that lies here.
  • Barchans (crescent shaped dunes) cover larger areas.
  • Longitudinal dunes more prominent here.
  • Because of arid climate with low vegetation cover – this is also known as Marusthali.

Coastal plains

  • Eastern Coastal Plain: The eastern coastal plain is broader and extends from West Bengal in the north to Tamil Nadu in the south. It includes regions like the deltas of the Ganges, Godavari, Krishna, and Kaveri rivers. This coastal plain is relatively wider and features fertile alluvial soil, making it agriculturally productive.
  • Western Coastal Plain: The western coastal plain is narrower compared to the eastern coastal plain. It stretches from Gujarat in the north to Kerala in the south, covering states such as Maharashtra, Goa, and Karnataka. The western coastal plain is characterized by a narrow strip of land between the Arabian Sea and the Western Ghats mountain range.

The islands

Lakshadweep Islands

  • These are a group of islands located in the Arabian Sea.
  • These are known for their pristine coral reefs.
  • The capital city of the Lakshadweep Islands is Kavaratti.
  • Also comprises of Laccadive, Minicoy, and Amindivi.
  • Pitti island is an uninhabited area and it has a bird sanctuary.

Andaman and Nicobar islands

  • These are a group of islands located in the Bay of Bengal.
  • These are an elevated portion of submarine mountains.
  • It lies close to equator and experience equatorial climate.
  • India’s only active volcano is found on Barren island in Andaman and Nicobar.
  • It is home to several indigenous tribes including Sentinelese, Jarawas, Great Andamanese, Onge, and Shompen.

Corals

  • Corals are marine invertebrate animals that form the foundation of coral reefs.
  • Coral reefs are made up of colonies of tiny coral polyps that secrete calcium carbonate to build a hard exoskeleton.
  • There are two main types of corals: hard corals and soft corals.
  • Hard corals, also known as stony corals, build rigid skeletons of calcium carbonate.
  • Soft corals have a flexible and fleshy structure.
  • Corals have a mutually beneficial relationship with tiny algae called zooxanthellae.
  • The zooxanthellae live within the coral tissues and provide the corals with oxygen and nutrients through photosynthesis.
  • In return, the corals offer protection and a habitat for the zooxanthellae.