INDIA: PHYSIOGRAPHICAL REGIONS
The physiographical regions of India make it a land of great diversity. About 11% of its total area is mountainous. Hills, plateaus and plains cover 18%, 28% and 43% respectively of its total area.
On the basis of geomorphology, India can be divided into the following four regions:
I.The Northern Mountain Region
II. The Deccan Plateau
III. The Great plains between the above two
IV. The Coastal plains and islands
I. The Northern Mountain Region
This mountain region of 2500 km is spread uninterruptedly from Jammu & Kashmir in the west to Arunachal Pradesh in the east. It is wider in the west (500 km) than in the east (200 km). Its main reason is that the compressive force was more in the east than in the west. That is why high mountain peaks like Mount Everest and Kanchenjunga are present in the Eastern Himalayas. The Himalayas are the result of the collision between the Eurasian plate (Angaraland) and the Indo-Australian plate (Gondwanaland). Before the Plate Tectonics theory, it was believed that the Himalayas originated as a result of the pressure on the deposited silt in the Tethys sea. Even the Plate Tectonics theory does not reject the contribution of their deposited silt in the formation of the Himalayas and the presence of the Tethys sea. Therefore, we can say that the Himalayas originated from the Tethys sea. The Himalayas are one of the newest fold mountains of the world, They have come up during the Tertiary epoch under Alpine earth movement.
The northern mountain region can be divided into three parts:
1. The Himalayan Mountain Region
2. The Trans-Himalayan Mountain Region
3. The Eastern or Purvanchal Hills
1. The Himalayan Mountain Region
There are three main mountain ranges under the Himalayan mountain region:
(a) The Great Himalayas or Inner Himalayan Range
(b) The Lesser Himalayas or the Himachal Range
(c) The Outer Himalayas or the Shiwalik Range
(A) The Great Himalayas => It is also known as the 'Himadri', the 'Main Himalayas' or the 'Snowy Himalayas'. It is extended from the gorge of the Indus river to the bend of the Brahamputra river in Arunachal Pradesh. The high peaks of the world are found in this range. The highest peak of this range is Mount Everest or Sagarmatha'. The slope of this range towards the north (towards the Indus and the Tsangpo rivers) is slow but steep towards the south. The Ganga, the Yamuna and their tributaries originate from the middle of this range. The Indus, the Brahmaputra and Alaknanda rivers have made antecedent valleys by passing through this range.
Important mountain peaks of the Great Himalayas are :
Antecedent river-The river which got its origin before the upliftment of the land mass is called an antecedent river. If the land mass rises on the way of the river, the antecedent river cuts the elevated landmass and keeps its old path and the valley intact.
1. Mount Everest (8848 m)
2. Kanchenjunga (8598 m)
3. Makalu (8481 m)
4. Dhaulagiri (8172 m)
5. Nanga Parbat (8126 m)
6. Annapurna (8076 m)
7. Nanda Devi (7817 m)
- The highest mountain peak of the Himalayas is Mount Everest. It is also the highest mountain peak of the world.
- The highest mountain peak in India is Mount K2, or Godwin Austin. Its height is 8611 m. It is situated in the Karakoram mountain range and is its highest peak. At present it is a part of the POK.
- The highest mountain peak of the Himalayas in India is Kanchenjunga. It is situated on the border of Sikkim and Nepal.
- The height of snowline is more in the west than in the east in the Great Himalayas. It means snow can be seen on a lower level in the eastern part than in the western. Its reason is that the western part is less humid than the eastern. Due to high humidity, the height of snowline in the Assam Himalayas is about 4400 m whereas due to low humidity, that in the Kashmir Himalayas is about 5100 m.
Higher Snowline in the Western Himalayas than that in the Eastern Himalayas
(B) The Lesser Himalayas or the Himachal Range =>
Its extension is in the south of the Great Himalayas. It is 80 to 100 km wide and its average height is between 3700 and 4500 m. There are several small ranges under the Lesser Himalayas which are as follows:
(i) Pir Panjal Range - It extends from the Jhelum to the Beas rivers in Kashmir and Uttarakhand. The two main passes in the Pir Panjal range are Banihal and Pir Panjal.
(ii) Dhauladhar Range -The place where Alaknanda river crosses the Great Himalayas near Badrinath, a range comes out from there towards the west in the south of the main range. This range is called Dhauladhar range. Its extension is mainly in Himachal Pradesh and partly in Uttarakhand.
(iii) Nag Tibba Range-The place where the river Kali Gandaki near Dhaulagiri peak (Nepal) passes through the Great Himalayas, a range comes out from there towards the west. It is known as Nag Tibba range.
(iv) Mahabharata Range -Its extension is in Nepal.
Valleys of Kashmir and Kathmandu
India : Physiographical Regions Two open valleys have developed between the Great Himalayas and the Lesser Himalayas:
(i) The Kashmir valley
(ii) The Kathmandu valley.
The valleys of Kashmir and Kathmandu have been created with the sedimentation of lakes. The Dal and the Wular lakes of Kashmir are its evidences. The valleys of Lahaul & Spiti and Kullu are between the Great and the Lesser Himalayas. There are small meadows found on the slopes of the Lesser Himalayas. They are called 'marg' in Kashmir (e.g. Gulmarg, Sonamarg) and 'bugyal' or 'payar' in Uttarakhand. [Gulmarg is famous as the centre of Winter Games.] Famous hill stations like Shimla, Mussoorie, Chakrata, Nainital, Ranikhet, Darjeeling etc are situated in the lower region of the Lesser Himalayas i.e., between the Lesser Himalayas and the Shiwalik range.
(C) The Outer Himalayas or the Shiwalik Range =>
The Shiwalik range is situated to the south of the Lesser Himalayas. It extends from Potwar basin of Punjab in the west to the Kosi river in the east. It is wider in Himachal Pradesh and Punjab, and gradually becomes narrower as it extends toward the east. This is the newest part of the Himalayas. Its average height is 600 to 1500 meters. The valley that separates the Shiwalik range from the Lesser Himalayas is known as 'dun' (e.g. Dehradun) in the west and 'duar' (e.g. Haridwar) in the east.
→ Main Central Thrust (MCT) -The Main Central Thrust has been marked as a dividing line between the Great Himalayas and the Lesser Himalayas. It is, in fact, a 2200 km - long large geological thrust fault which separates the geological structure of the Great and the Lesser Himalayas. A thrust fault is that fault where the land sliding up or down by the fault line also slides towards one another and mounts on one another. It is also called 'reverse fault'.
→ Great Boundary Fault (GBF) -The place where the Aravali mountain, in its eastern boundary region meets the Vindhyas, a geological thrust fault has been formed between these two mountains, It is known as the Great Boundary Fault.
→ Main Boundary Thrust (MBT) -A large geological thrust fault has been formed between the Lesser Himalayas and the Shiwalik range. It is known as the Main Boundary Thrust.
2. Trans-Himalayan Mountain Region or the Tibet Himalayan Range
It is situated to the north of the Great Himalayas. It has Karakoram. Ladakh, Zaskar and Kailash mountain ranges. The Karakoram range is called the backbone of high Asia.
Various Mountain Ranges in the Trans-Himalayan Mountain Region
The mountainous complexities of the Himalayan region can be understood in a simple way with the help of the above figure. The Indus river flows between Zaskar and Ladakh ranges. It creates the deepest gorge in India (5200 m deep) by cutting Ladakh range at the place named Bunzi.
(1) The Eastern or Purvanchal Hills => These are extended in the north-eastern states of India. Several of these hills are extended along the border of India and Myanmar (viz. the Patkai Bum Hills, the Naga Hills, and the Mizo Hills) while others are inside India. The major among the Purvanchal Hills can be seen in the following map:
Rivers and Hills in Purvanchal (North-East India)
It would be better to have a look at the important Indian passes found in the Himalayan region.
Important Passes in India
India : Physiographical Regions
- Zoji La (Pass)-It is in the Zaskar range of Jammu & Kashmir. The road route from Srinagar to Leh goes through this pass.
- Banihal Pass-It is in Jammu & Kashmir. The National Highway No.1A that links Srinagar to Jammu goes through it.
- Shipki La (Pass)-It is in Himachal Pradesh. The road from Shimla to Tibet goes through this pass. The Satluj river flows through this pass.
- Baralacha Pass-It is also in Himachal Pradesh. It links Mandi and Leh by road.
- Rohtang Pass-It is also in Himachal Pradesh. It cuts through the Pir Panjal range. It links Manali and Leh by road.
- Mana Pass-It is in Uttarakhand. The land route to the Kailash and the Manasarovar passes through it.
- Niti Pass-It is also in Uttarakhand. The road to the Kailash and the Manasarovar passes through it.
- Nathu La (Pass)-It is in Sikkim. It gives way to Tibet from Darjeeling and Chumbi valley. The Chumbi river flows through this pass.
- Jelep La (Pass)-It is also in Sikkim and gives way to Bhutan. The Tista river has created this pass.
The Deccan Plateau
It is the oldest plateau not only in India but also in the world. It is made up of the Archaean period rocks and its no part has ever submerged in the sea (Some evidences of its temporary local submergence near the Eastern Ghats have been found). Since it is tectonically a placid region, the possibility of an earthquake is very less. However, the earthquakes Occurred in Koyna and Latur have put a question mark on it. The hills of Aravali, Kaimur, Rajmahal, and Shillong make the northern border of the peninsular plateau. Its southern tip is Kanyakumari which touches the Indian Ocean. There are the Eastern Ghats slightly west to the coastal Plain on its eastern border. They are in the form of residual mountains which are not regular but broken at intervals. The Western Ghat mountains are situated on the western side of the deccan plateau. They are in the form of a block mountain. In the process of separation from India from Africa, a fault valley has been formed in the form of the Arabian Sea, and the Western Ghats have been left as the escarpment of this fault valley. The steep slope of the western Ghats of the peninsular India shows that fault.
The Peninsular Plateau of India
The mountains of the peninsular plateau can be understood in detail by dividing them under the following sub-heads:
It is a residual mountain range. It is one of the oldest fold mountain ranges in the world. The length of the Aravallis is about 800 km which extends from Delhi to Palanpur (Gujarat)h, It is known as 'Jarga' near Udaipur and 'Delhi Ridge' near Delhi. Its highest peak is Guru Shikhar. It is on the Abu hills. Mt. Abu is a famous hill station. [The Brahmakumaris had established the world's largest solar vapour cooking system on Mt. Abu. Presently, the world's largest solar vapour cooking system is at Shirdi, Ahmednagar, Maharashtra. Dilwara Jain temple, the famous religious place for the Jains is situated on Mt. Abu.]
(b) The Western Ghat Mountain Range or the Sahyadri Range
The Western Ghat mountain range is India's second largest mountain range after the Himalayas. Its length is about 1500 km. This range extends from the Tapi river valley to the Nilgiri hills.This range is also known as the Sahyadri range. It is divided into two parts-the North Sahyadri and the South Sahyadri. The 16°N latitude which passes through Goa is the dividing line between them. There is a lava deposition on the upper surface of the northern Sahyadri. The South Sahyadri is made up mainly of Archean rocks (granite and gneiss). The highest peak of the North Sahyadri is 'Kalsubai' (1646 m) whereas that of the South Sahyadri is 'Kudremukh' (1892 m). The second highest peak of the South Sahyadri is 'Pushpagiri (1714 m). The Kaveri river originates near Pushpgiri. The Nilgiri hills are a physiographic knot where the Eastern Ghats and the Western Ghats meet together. The highest peak of the Nilgiris is 'Doddabetta' (2623 m) which is the second highest peak of South India, the highest being 'Anamudi' (2695 m) peak of the Annamalai mountain which is extended in the north- south direction on the borders of Kerala and Tamil Nadu to the south of the Nilgiris.
There are Cardamom hills to the south of the Annamalai mountain and the Nagercoil hill is to the south of the Cardamom hills. Their location can be seen in fig 2.9. To the south of the Annamalai mountain emerges the Palni hill which has north-east direction.
Location of Nilgiri and the Annamalai mountain
Location of the Palni Hills
The famous hill station 'Kodaikanal' (Tamil Nadu) is on the Palni hill whereas 'Ooty' (Udagamandalam or Ootacamund) is located on the Nilgiris in Tamil Nadu. The 'Gersoppa' or 'Jog' (Mahatma Gandhi) waterfall on Sharavathi river is located in the Western Ghats. This is India's highest waterfall. There are four main passes that have developed in the Western Ghats. Their location from the north to the south is as follows:
- Thal Ghat-It links Nasik to Mumbai. We can say that it connects Kolkata to Mumbai because the route leading from Kolkata to Mumbai passes through Nasik.
- Bhor Ghat-It links Mumbai to Pune.
- Pal Ghat-This pass is located between the Nilgiris and the Annamalai mountain. It is in Kerala and connects Kochi and Chennai, the two main cities of the south India.
- Senkota pass - This pass located between the Nagercoil and the Cardamom hills links Thiruvananthapuram and Madurai.
(c) The Eastern Ghat Mountain Range =>
This mountain range extends from Odisha to Tamil Nadu. It is a residual form of the old fold mountain. It has been more eroded than the Western Ghats. Therefore, It is of less height than that. Its continuity is almost over because of river-erosion. The rivers like the Godavari and the Krishna have developed very wide valleys by cutting it. The real height and actual mountainous characters of this mountain range are seen between the Mahanadi and the Godavari rivers. Of the highest peaks of the Eastern Ghat mountains, different names at different places have been mentioned. Here, the names of some main peaks are given below : Jindhagada peak, Visakhapatnam (1690 m), Mahendragiri (1501 m), Niyamgiri (1515 m), etc.
We were till now discussing about the main mountains of the peninsular India which are located on its three sides. Now we shall study the inner hills of the peninsular plateau.
The Satpura range is famous among the inner hills. It is a group of the Satpura, the Mahadev and the Maikal hills. The Satpura range is a block mountain which has the valley of the Narmada river on its northern side and that of the Tapi on the western side.
Satpura Mountain Range
Block Mountain-The middle portion of a landmass that stands like a mountain in case of the portions flanking on both sides sink down, is called a block mountain.
The highest peak of the Mahadev hills is 'Dhoopgarh' (1350 m) which is also the highest peak of the Satpura range. The highest peak of the Maikal hills is 'Amarkantak' from where two prominent rivers, the Narmada and the Son originate. The readers should note that three rivers do originate from the three sides of the Maikal hills (as it is shown in the figure 2.11) but, from Amarkantak, only two rivers, the Narmada and the Son originate and not the Mahanadi. The famous hills station 'Pachmarhi in Madhya Pradesh is near Dhoopgarh.
The rivers in the Satpura range make several waterfalls among which the 'Dhuandhar' waterfall on the Narmada is important. There are marble rocks found here.
The second prominent mountain range among inner hills is the Vindhyachal mountain range. This range is a group of the Vindhyachal, the Bhander, the Kaimur and Parasnath hills. A freehand figure has been drawn below to show the complexities of these hills.
The Vindhyachal Mountain Range
According to geologists the Vindhyachal mountain range is only the escarpment of the rift valley of the Narmada in the same way as the Kaimur hill is of the Son river. The slope of the peninsular India is towards the east or little south-east. That is why rivers like the Godavari and the Krishna originating from the Western Ghats, instead of flowing into the nearby the Arabian Sea, cover a long distance in the eastern direction and flow into the Bay of Bengal. However, the Narmada and the Tapi are exceptions. They do not flow in the direction of the east but the west and drain into the Arabian Sea. It happens because they flow in rift valleys.
The peninsular India is divided into several small plateaus. Here we shall discuss them in brief and request the readers to see the locations of these plateaus in an atlas:
(i) The Malwa Plateau - It is a lava plateau and at present, is a peneplain of black soil. There are the hills of Gwalior to the north of this plateau. There are the plateaus of Bundelkhand and Baghelkhand on the north and the north-eastern borders.
(ii) The Bundelkhand Plateau - This plateau is between the Gwalior plateau and the Vindhyas. This region is known as the 'badland topography' because of the 'ravines' formed by the Chambal river. There are 'river terraces' in the Chambal that hint for the rejuvenation of this region. This plateau is made up of the Bundelkhand gneiss.
(iii) The Baghelkhand Plateau - It is spread to the east of the Vindhya range (Kaimur and the Bhander hills).
(iv) The Chotanagpur Plateau - The Rajmahal hills are its north boundary. The Mahanadi makes its south boundary. The flows to its north-west and meets with the Ganga near Patna. The Damodar river creates a rift valley in its middle portion and flows from the west to the east (The Damodar is a tributary of the Hugli). There are the plateaus of Hazaribagh and Koderma to its north and that of Ranchi is to its south. The Chotanagpur plateau is highly rich in mineral resources.
(v) The Deccan Plateau-It is divided into three parts:
- The Deccan lava plateau
- The Telangana plateau
- The Karnataka (Mysore) plateau
(a) The Deccan lava plateau - This plateau is made up of the basalt-rich lava that came out as a result of fissure eruption during the Cretaceous period in South India. At present the black cotton soil has developed on it which is very fertile.
The Lonar lake is located in Buldana district of Maharashtra., It is built on the Deccan basalt rock of the Cretaceous period. The scholars hold different opinions regarding its origin. Several scholars opine that the Lonar is a crater (mouth of a volcano)1, The flow of lava during the Cretaceous period and the earthquakes occurred in Latur and Koyna in recent times support this opinion.
The other group of scholars opine that it has been built as a result of a large depression made by collision of a meteorite. According to the Geological Survey of India (GSI), the Lonar lake has been built due to collision of a large meteorite.
(b) The Telangana plateau - It was extended in the interior region of undivided Andhra Pradesh. At present, it is extended in Telangana and southern Andhra Pradesh. Geomorphologically, the upper surface of this plateau is almost like a peneplain. This plateau has been divided into two parts. Its northern part is known as 'Telangana' and the southern part 'Rayalaseema'. Rayalaseema highland is a complete peneplain developed on the surface of gneiss. The river Penner flows through its central part. The slope of both Telangana and Rayalaseema plateaus is towards east. The cretaceous lava deposits are found in the northern and western parts of Telangana plateau. One can find the deposits of rocks of Dharwad system in Anantapur area and Cuddapah system in Guntur, Kurnool and Cuddapah areas.
(c) The Karnataka (Mysore) plateau - The Baba Budan Hills are the part of this plateau. It is rich in iron ore. The Kaveri is the main river of the Karnataka (Mysore) plateau.
(vi) The Dandakaranya plateau - The expansion of this plateau Is in south Chhattisgarh and eastern Maharashtra. It is uneven and infertile region.
(vii) The Meghalaya plateau-It is originally the eastern extension of the Deccan plateau. The Garo, the Khasi and the Jaintia hills are located in this plateau from the west to the east respectively. ‘Cherrapunji’ and ‘Mawsynram’ are situated to the south of the khasi hills. It is also known as the Shillong plateau.
The Hills of Meghalaya
(viii) Garhjat Hills - It is also known as the Odisha highland. It is extended in the western part of the coastal plains (Utkal coast) of Odisha from the north-east to the south-west direction. The Chotanagpur plateau is situated in its north, the Mahanadi valley in its west and the Eastern Ghat mountains in its south-west. The prominent peaks of this area are Mahendragiri (1490 m), Malayagiri (1169 m), etc.
III. The Great Plains of India
This plain is located between the Himalayas and the peninsular India. The rivers originating from the Himalayas (e.g. the Ganga, the Yamuna, the Indus, the Brahmaputra, the Kosi etc) and those originating from the peninsular India (e.g. the Son, the Chambal etc) have created this fertile plain by depositing alluvial soil there.
On the bases of structural characteristics and slope, this plain can be divided into four parts:
The bhabar lies all along the foothills of the Shiwaliks with a remarkable continuity from the Indus to the Tista.
- It is a porous and pebbled plain. It has been created by the deposition of granules and pebbles brought by the rivers descending from the Himalayas. It is also known as the 'alluvial fan' of the Shiwaliks.
- The rivers flowing through this region disappear ,i.e., they flow under the pebbles because of too much porosity and are invisible on the ground.
(b) The Terai Region
Its expansion is exactly to the south of the bhabar region, The deposition of fine sand and mud is found here.
- The rivers that disappear in the bhabar region re-appear on the surface in the terai region.
- Since this region is very much plane, the river water spreads here and there, and makes it a marshy land.
- Since this region is very much plane, the river water spreads here and there, and makes it a marshy land.
(c) Bangar (Bhangar)
It is made of old alluvial soil. It is a higher region than khadar, Normally, the flood water does not reach this region.
- The expansion of the bangar region is found in the region between two rivers (doab). The Ganga-Yamuna doab and the plain of the Satluj are its examples.
- The bangar has two regional types-
- Barind field
- Bhur area
- The barind field is situated in the delta regions of Bengal which is really the delta of the Ganga. It was created in the Pleistocene period, Then it was raised up and it has become an area of laterite soil after erosion.
The development of 'bhur' has occurred in the upper Ganga-Yamuna doab. It has been made by the deposition by wind in the Pleistocene period. Today, it is found in the form of a continuous ridge on the bangar highlands. A special kind of 'bhur' soil in which gravel (kankar) and sand are found has been made by these ridges in the districts of Moradabad and Bijnor in the doab region.
- In some areas of the bangar soil, a white layer of salt is deposited here and there on the land because of too much irrigation. It is known as 'reh' or 'kallar'.
This plain has been made by the deposition of new alluvial soil and is rather low lad. Here the flood water reaches almost every tear making this plane fertile.
- These regions of Bihar, eastern Uttar Pradesh and West Bengal adjacent to the river valleys come under khadar region. The delta of the Ganga-Brahmaputra is also an example of khadar.
- In uttar Pradesh and the adjacent regions, this low land is called ‘Khadar’ whereas in Punjab it is called ‘net’.
On the regional basis this great plain can be divided into following sub-heads:
(i) The Indus Plain
It is spread in the Indus river valley. The plain west to the Indus is made up mainly of bangar. The plain lying to the east of the river is typically deltaic in relief. This side the remains of old river beds are found typically deltaic in relief. This side the remains of old river beds are found on the surface of new alluvial deposition. These are found as long and narrow depressions called ‘dhoros’.
- Numerous saliferous lakes are found near dry river beds which are locally called ‘dhands’, e.g. Purvi Nara.
(ii) The Plain of Punjab
This plain is spread in the states of Punjab and Haryana.
- This is made up mainly of bangar but khadar land is found along the rivers in a narrow belt which is called ‘bet’ in local language.
- The significant characteristics of this plain are Panch-doabs (doabs of five rivers) which have special names
- Bist doab - doab between the Beas and the Satluj
- Bari doab - doab between the Beas and the Ravi.
- Rachna doab - doab between the Ravi and the Chenab.
- Chhaj doab - doab between the Chenab and the Jhelum.
- Sindh sagar doab - doab between the Jhelum-Chenab and the Indus.
- In the plain of Punjab, the river courses have created flat khadar floodplains by cutting the ,ass of alluvium. Bluffs (Cliffs of low height) have developed on its both sides which are called ‘dhaya’ in local language.
AREA OF PANCH DOABS
(iii) The Plain of Rajasthan
The expansion is from the west of the Aravallis to the Indo-pakistan border. The main river of this plain is Luni which disappears in the Rann of Kachchh. The Sambar and the Didwana are major salt lakes of this plain. The Sambhar is the largest inland salt lake in India, Its area is about 190 sq.km.
(iv) The Gangetic Plain
The expansion of this plane is in the states of Uttar Pradesh, Bihar and west bengal. The northern plain of the Ganga in Uttar Pradesh can be divided into two parts - The western part is known as the Plain of Rohilkhand whereas the eastern part is called the Plains of Awadh. This plain running from the origin of the Ganga to its mouth can be divided into three parts.
- The Upper Gangetic plain - Western Uttar Pradesh
- The Middle Gangetic PLain - Eastern Uttar Pradesh and North
- The Lower Gangetic plain - West Bengal
- There are depression (low lands) in the Gangetic plain here and there. This depression is called ‘Jalla’ near Patna and ‘tal’ near Mokama. The low and which is filled with water is known as ‘bil’ in West Bengal.
- There are too many oxbow lakes in the Middle Gangetic plain because rivers meander in this plane.
(v) The Brahmaputra Plain
It is a long and narrow plain situated between the Himalayas and the Meghalaya plateau. The name of this plain suggests that this plain has been developed by the Brahmaputra and its tributaries. Several islands have originated because of the deposition of sol in the middle of the Brahmaputra. Majuli is such an island which is in Assam. It is the largest riverine island in the world. At present, the existence of this island is in danger because of erosion by the river.
IV. The Coastal Plains and the Island Groups
The expansion of the coastal plains has occurred between the peninsular mountain ranges and the sea coasts of India.
The sedimentation by both sea and rivers has contributed in the formation of these pains. The coastal plain can be divided into two parts:
i. The Western Coastal Plain ii. The eastern Coastal Plain.
(i). The western Coastal Plain
This plain extends from Surat to Kanyakumari. It can be divided into four parts:
- The Gujarat plain - between area of Gujarat.
- The Konkan plain - between Daman and Goa.
- The Kannad plain - between Goa and Mangalore.
- The Malabar plain - between Mangalore and Kanyakumari
The maximum expansion of the western coastal plain is about 80 km near the mouths of the Narmada and the Tapi in Gujarat. Most of the rivers flowing in the western coastal plain originate from the western slope of the Western Ghats. These rivers are small and rapid. Most of them from estuaries instead of deltas at their mouths. Some backwaters are found on the wesstern coast which are called kayal in kerala, e.g. Vembanad and Ashtamudi.
(ii). The Eastern Coastal Plain
This plain extends between the Eastern Ghats and the sea coast from Subarnarekha river to Kanyakumari. The eastern coastal plain is wider than the western coastal plain. The main reason of it is the large scale erosion of the Eastern Ghat mountains and the formation of large delta at the mouths of rivers likes the Godavari, the Krishna and the Kaveri. In the eastern coastal plain, there is the Kolleru lake (Andhra Pradesh) in the delta region of the Godavari and the Krishna. It is a deltaic lake. There are two more important lakes on the eastern coast of India-the Chilika Lake (in Odisha) and the Pulicat Lake (On the border of Andhra Pradesh and Tamil Nadu). Both are the examples of lagoon, The Chilka Lakes is the largest saltwater lake and lagoon lake in India. Its area is about 3560 sq.km. The Odishan plain is also known as the Utkal Plain. The easern coastal plain between the Godavari and the Mahanadi is known as the Northern Circar whereas the eastern coast of TAmil Nadu is called the Coromandel coast.
The Island Groups
The Indian island groups can generally be divided into two parts:
(i) The Andaman and Nicobar island situated in the Bay of Bengal.
(ii) The Lakshadweep Islands adjacent to the Kerala coast (in the Arabian Sea)
(i) The Andaman and Nicobar island -
- The Andaman and Nicobar islands are originally the protruded parts of the oceanic fold mountains formed during the Tertiary epoch. Here, there are about 350 islands in which only 38 are inhabited.
- The highest peak of the Andaman and Nicobar islands is ‘Saddle Peak’ (North Andaman, 738 m) followed by ‘Mt. Thullier’ (Great Nicobar, 642 m).
- The Barren Island, an island of this archipelago, is the only active volcano in India.
- The Andaman and Nicobar Islands are larger than the Lakshadweep Island, both in area and population.
(ii) The Lakshadweep Islands
The Lakshadweep islands are situated in the Arabian Sea at a distance of 220-240 km from the western coast of the Indian mainland. There are 36 islands in this archipelago (total area = 32 sq km) in which only 10 are inhabited. Most of the islands are plain. The height of the islands is nowhere more than 2 m above the sea-level. These islands have been formed by the deposition of corals on the Chagos-Lakshadweep Undersea Ridge. The atolls found in the oceanic region of India are situated mostly in Lakshadweep. An atoll is a kind of coral reef which looks like a ring or horseshoe. The attols are the regions of high biodiversity. The islands are surrounded by the coral reefs which abound in coconut trees.
Kavaratti is the capital of Lakshadweep. Agatti is the only island having an airport. Andrott is the largest island (4.9 sq km) of Lakshadweep archipelago. Minicoy is the second largest (4.8 sq km) and Southernmost island of this archipelago. Coconut is the only agricultural product and fishing the main occupation here. 'Tuna' is the mostly caught fish. A small industry has been established for its packaging in Minicoy. Pitti or Pakshipitti is an uninhabited coral islet here which has been declared as a bird sanctuary.
Most of the inhabitatns of this island group have come from the Malabar coast. About 94% of the population here is Muslim which is related to the Shafi School of the Sunni Sect. Malayalam is spoken in all the islands. Minicoy is an exception where 'Mahl' is spoken. Mahl is written in Divehi script. It is originally a Maldivian language. All the natives of the Lakshadweep islands are Scheduled Tribes. According to the 2011 census 94.6% of the population here is Scheduled Tribe. Here, there is no population of Scheduled castes.
Some other prominent islands of India
(i) Sriharikota-It is situated in the foremost part of Pulicat Lake. It is made up of coral reefs.
(ii) Pamban island-It is situated in the Gulf of Mannar between India and Sri Lanka. It is a part of the Adam's Bridge.
(iii) New Moore island-It is situated in the Bay of Bengal on the border of Bangladesh and India. It is the latest island made up of deposition of silt at the mouth of the Ganga.
(iii) New Moore island - It is situated in the Bay of Bengal on the border of Bangladesh and India. It is the latest island made up of deposition of silt at the mouth of the Ganga.
There had been dispute between India and Bangladesh over New Moore island and also over 25,000 sq. Km oceanic region on the maritime borders of both the countries. A case was filled in October 2009 by the Government of Bangladesh for settlement of this dispute at the Permanent Court of Arbitration (PAC) which gave its verdict in July 2014. The PAC based at the Hague, Netherlands expressed in its verdict that 19,467 sq. Km. of the disputed 25,000 sq. Km. area would go to Bangladesh and the rest to India. Since the location of New Moore Island is in the oceanic region awarded to India, the latter (India) has got full sovereignty over the formor (New Moore Island).