Gist of NCERT
INDIA - LOCATION
The mainland of India, extends from Kashmir in the north to Kanniyakumari in the south and Arunachal Pradesh in the east to Gujarat in the west. India’s territorial limit further extends towards the sea upto 12 nauticalmiles (about 21.9 km) from the coast. (See the box for conversion).
Statute mile= 63,360 inches
Nautical mile= 72,960 inches
1 Statute mile= about 1.6 km (1.584 km)
1 Nautical mile= about 1.8 km (1.852 km)
Our southern boundary extends upto 6º45 N latitude in the Bay of Bengal
If you work out the latitudinal and longitudinal extent of India, they are roughly about 30 degrees, whereas the actual distance measured fromnorth to south extremity is 3,214 km, and that fromeast to west is only 2,933 km. What is the reason for this difference?
This difference is based on the fact that the distance between two longitudes decreases towards the poles whereas the distance between two latitudes remains the same everywhere.
From the values of latitude, it is understood that the southern part of the country lies within the tropics and the northern part lies in the subtropical zone or the warm temperate zone. This location is responsible for large variations in land forms, climate, soil types and natural vegetation in the country.
There is a general understanding among the countries of the world to select the standard meridian in multiples of 7º30 of longitude. That is why 82º30 E has been selected as the ‘standard meridian’ of India. Indian Standard Time is ahead of Greenwich Mean Time by 5 hours and 30 minutes
There are some countries where there are more than one standard meridian due to their vast eastto- west extent. For example, the USA has seven time zones.
Now, let us observe the extent and its implications on the Indian people. From the values of longitude, it is quite discernible that there is a variation of nearly 30 degrees, which causes a time difference of nearly two hours between the easternmost and the westernmost parts of our country. What is the use of the standard meridian? While the sun rises in the northeastern states about two hours earlier as compared to Jaisalmer, the watches in Dibrugarh, Imphal in the east and Jaisalmer, Bhopal or Chennai in the other parts of India show the same time. Why does this happen?
Name a few place in India through which the standard meridian passes?
India with its area of 3.28 million sq. km accounts for 2.4 per cent of the world’s land surface area and stands as the seventh largest country in the world.
Structure and Physiography
Current estimation shows that the earth is approximately 4600 million years old.
Based on the variations in its geological structure and formations, Indian can be divided into three geological divisions. These geological regions broadly follow the physical features
(i) The Peninsular Block
(ii) The Himalayas and other Peninsular Mountains
The Peninsular Block
The northern boundary of the Peninsular Block may be taken as an irregular the running from Kachchh along the western flank of the Aravali Range near Delhi and then roughly parallel to the Yamuna and the Ganga as far as the Rajmahal Hills and the Ganga delta. Apart from these, the Karbi Anglong and the Meghalaya Plateau the the northeast and Rajasthan in the west are also extensions of this block. The northeastern parts are separated by the Media fault in West Bengal from the Chotanagpur plateau. In Rajasthan, the desert and other desert-like features overlay this block.
The Peninsula is formed essentially by a great complex of very ancient gneisses and granites, which constitutes as major part of it. Since the Cambrian period, the Peninsula has been standing like a rigid block with the exception of some of its western coast which is submerged beneath the sea and some other parts changed due to tectonic activity without affecting the original basement. As a part of the Indo-Australian Plate, it has been subjected to various verticalmovements and block faulting. The rift valleys of the Narmada, the Tapi and the Mahanadi and the Satpura block mountains are some examples of it. The Peninsula mostly consists of relict and residual mountains like the Aravali hills, the Nallamala hills, the Javadi hills, the Veliconds hills, the Palkonda range and the Mahendragiri hills, etc. The river valleys here are shallow with low gradients.
Most of the east flowing rivers form deltas before entering into the Bay of Bengal. The deltas formed by the Mahanadi, the Krishna, the Kaveri and the Godavari are important examples.
The Himalayas and other peninsular mountains
The Himalayas along with other peninsular mountains are young, weak and flexible in their geological structure unlike the rigid and stable peninsular Block, Consequently, they are still subjected to the interplay of exogenic and endogenic forces, resulting in the development of faults, folds and thrust plains. These mountains are tectonic in origin, dissected by fast-flowing rivers which are in their youthful stage. Various landforms like gorges, V-shaped valleys, rapids, waterfalls, etc. are indicative of this stage
The third geological division of India comprises the plains form by the river Indus, the Ganga and the Brahmaputra. Originally, it was a geo-synclinal depression which attained its maximum development during the third phase of the Himalayan during the third phase of the Himalayan mountain formation approximately about 64 million years ago. Since then, it has been gradually filled by the sediments brought by the Himalayan and Peninsular rivers. Average depth of alluvial deposits in these plains ranges from 1,000-2,000 m.
‘Physiography’ of an area is the outcome of structure, process and the stage of development.
Based on these macro variations, India can be divided into the follow physiographic divisions:
(i) The Northern and Northeastern Mountains
(ii) The Northern Plain
(iii) The Peninsular Plateau
(iv) The Indian Desert
(v) The Coastal Plains
(vi) The Islands.
North and North Eastern Himalaya:
Formation of Physical features of north and north-eastern Himalay is a result of “Plate tectonics” According to Plate Tectonic theory earth is divided into several plateau. The formation of Himalaya & north eastern mountain is due to convergent of two plates Eurasia (North ofHimalaya) and Gondwana (Indian subcontinents Australia, South Africa, South America). Both the plates came close to each other and tethys sediment called geosynclines was pressed from two sides gave birth to current Himalaya mountains.
The Himalayan uplift out of the Tethys sea and subsidence of the northern flank of the peninsular plateau resulted in the formation of a large basin. In due course of time this depression, gradually got filled with deposition of sediments by the rivers flowing from the mountains in the north and the peninsular plateau in the south. A flat land of extensive alluvial deposits led to the formation of the northern plains of India.
The land of India displays great physical variation. Geologically, the Peninsular Plateau constitutes one of the ancient landmasses on the earth’s surface. It was supposed to be one of themost stable land blocks. The Himalayans and the Northern Plains are the most recent landforms. From the view point of geology, Himalayan Mountains form an unstable zone. The whole mountain system of Himalaya represents a very youthful topography with high peaks, deep valleys and fast flowing rivers. The northern plains are formed of alluvial deposits. The peninsular plateau is composed of igneous and metamorphic rocks with gently rising hills and wide valleys.
The Himalayan Mountains
The Himalayas, geologically young and structurally fold mountains stretch over the northern borders of India. These mountain ranges run in a westeast direction fromthe Indus to the Brahmaputra. The Himalayas represent the loftiest and one of the most rugged mountain barriers of the world. They form an arc, which covers a distance of about 2,400 Km. Their width varies from 400 Km in Kashmir to 150 Km in Arunachal Pradesh. The altitudinal variations are greater in the eastern half than those in the western half. The Himalaya consists of three parallel ranges in its longitudinal extent. A number of valleys lie between these ranges. The northern most range is known as the Great or Inner Himalayas of the ‘Himadri’. It is the most continuous range consisting of the loftiest peaks with an average height of 6,000 metres. It contains all the prominent Himalayan peaks.
The folds of Great Himalayas are asymmetrical in nature. The core of this part of Himalayas is composed of granite. It is perennially snow bound, and a number of glaciers descend fromthis range
The range lying to the south of the Himadri forms the most rugged mountain system and is known as Himachal or lesser Himalay. The ranges are mainly composed of highly compressed and altered rocks. The altitude varies between 3,700 and 4,500 metres and the average width is of 50 Km. While the Pir Panjal range forms the longest and the most important rage, the Dhaula Dhar and the Mahabharat ranges are also prominent ones. This range consists of the famous valley of Kashmir, the Kangra and Kullu Valley in Himachal Pradesh. This region is well known for its hill stations
Karewas are the thick deposits of glacial clay and other materials embedded with moraines.
The outer most range of the Himalayas is called the Shiwaliks. They extend over a width of 10.50 Kmand have an altitude varying between 900 and 1100 metres. These ranges are composed of unconsolidated sediment brought down by rivers from the main Himalayans ranges located farther north. These valleys are covered with thick gravel and alluvium. The longitudinal valley lying between lesser Himalaya and the Shiwaliks are known as Duns. Dehra Dun, Kotli Dun and Patli Dun are some of the well-known Duns.
An Interesting Fact in Kashmir Valley, the meanders in Jhelum river are caused by the local base level provided by the erstwhile larger lake of which the present Dal lake is a small part.
There are large-scale regional variations within the Himalayas. On the basis of relief, alignment of ranges and other geomorphological features the Himalayas can be divided into the following subdivisions:
(i) Kashmir or Northwestern Himalayas
(ii) Himachal and Uttaranchal Himalayas
(iii) Darjeeling and Sikkim Himalayas
(iv) Arunachal Himalayas
(v) Eastern Hills and Mountains
Kashmir or Northwestern Himalayas
It comprise a series of ranges such as the Karakoram. Ladakh. Zaskar and Pir Panjal. The northeastern part of the Kashmir Himalayas is a cold desert, which lies between the Greater Himalayas and the Karakoram ranges. Between the Great Himalayas and the Pir Panjal range, lies the world famous valley of Kashmir and the famous Dal Lake. Important glaciers of South Asia such as the Baltoro and Siachen are also found in this region. The Kashmir Himalayas are also famous for Karewa formations, which are useful for the cultivation of Zafran, a local variety of saffron. Some of the important passes of the region are Zoji La on the Great Himalayas. Banihal on the Panjal, Photu La on the Zaskar and Khardung La on the Ladakh range. Some of the important fresh lakes such as Dal and Wular and salt water lakes such as Pangong Tso and Moriri are also in this region. This region is drained by the river Indus, and its tributaries such as the Jhelum and the Chenab. The Kashmir and northwestern Himalayas are well-known for their scenic beauty and picturesque landscape. The landscape of Himalayas is a major source of attraction for adventure tourists. Some famous places of pilgrimage such as Vaishno Devi, Amarnath Cave, Charar -e-Shariff, etc. are also located here and large number of pilgrims visits these places every year
Srinagar, capital city of the Jammu and Kashmir is located on the banks of Jhelum river. Dal Lake in Srinagar presents an interesting physical feature. Jhelum in the valley of Kashmir is still in its youth stage and yet forms meanders- a typicalfeature associated with the mature stage in the evolution of fluvial land form (Figure).
The southernmost part of this region consists of longitudinal valleys known as ‘duns’. Jammu dun and Pathankot dun are important examples.
The Himachal and Uttaranchal Himalays
This part lies approximately between the Ravi in the west and the Kali (a tributary of Ghaghara) in the east. It is drained by two major river systems of India, i.e. the Indus and the Ganga. Tributaries of the Indus include the river Ravi, the Beas and the Satluj, and the tributaries of Ganga flowing through this region include the Yamuna and the Ghaghara. The northernmost part of the Himachal Himalayas is an extension of the Ladakh cold desert, which lies in the Spiti subdivision of district Lahul and Spiti. All the three ranges of Himalayas are prominent in this section also. These are the Great Himalayan range, the Lesser Himalayas (which is locally known as Dhaoladhar in Himachal Pradesh and Nagtibha in Uttaranchal) and the Shiwalik range from the North to the South. In this section of Lesser Himalayas, the altitude between 1,000-2,000 m specially attracted to the British colonial administration, and subsequently, some of the important hill stations such as Dharamshala, Mussoorie, Shimla Kaosani and the cantonment towns and health resorts such as Shimla, Mussoorie, Kasauli, Almora, Lansdowne and Ranikhet, etc. were developed in this region.
The two distinguishing features of this region from the point of view of physiography are the ‘Shiwalik’ and ‘Dun formations’. Some important duns located in this region are the Chandigarh- Kalka dun, Nalagarh dun,DehraDun,Harike dun and the Kota dun, etc. Dehra Dun is the largest of all the duns with an approximate length of 35-45 km and a width of 22-25 km. In the Great Himalayan range, the valleys are mostly inhabited by the Bhotia’s. These are nomadic groups whomigrate to ‘Bugyals’ (the summer grasslands in the higher reaches) during summer months and return to the valleys during winters. The famous ‘Valley of flowers’ is also situated in this region. The places of pilgrimage such as the Gangotri, Yamunotri, Kedarnath, Badrinath and Hemkund Sahib are also situated in this part. The region is also known to have five famous Prayags (river confluences). Can you name some other famous prayags in other parts of the country?
The Darjeeling and Sikkim Himalayas
They are flanked by Nepal Himalayas in the west and Bhutan Himalayas in the east. It is relatively small but is a most significant part of the Himalayas. Known for its fast-flowing rivers such as Tista, it is a region of high mountain peaks like Kanchenjunga (Kanchengiri), and deep valleys. The higher reaches of this region are inhabited by Lepcha tribes while the southern part, particularly the DarjeelingHimalayas, has amixed population of Nepalis, Bengalis and tribals from Central India. The British, taking advantage of the physical conditions such as moderate slope, thick soil cover with high organic content, well distributed rainfall throughout the year and mild winters, introduced tea plantations in this region. As compared to the other sections of the Himalayas, these along with the Arunachal Himalayas are conspicuous by the absence of the Shwalik formations. In place of Shwaliks here, the ‘duar formations’ are important, which have also been used for the development of tea gardens. Sikkim and Darjeeling Himalayas are also known for their scenic beauty and rich flora and fauna, particularly various types of orchids.
The Arunachal Himalayas
These extend from the east of the Bhutan Himalayas upto the Diphu pass in the east. The general direction of the mountain range is from southwest to northeast. Some of the important mountain peaks of the region are Kangtu and Namcha Barwa. These rangers are dissected by fast-flowing rivers from the north to the south, forming deep gorges. Brahmaputra flows through a deep gorge after crossing Namcha Barwa. Some of the important rivers are the Kameng, the Subansiri, the Dihang and the Lohit. These are perennial with the high rate of fall, thus, having the highest hydro-electric power potential in the country. An important aspect of the Arunachal Himalayas is the numerous ethnic tribal community inhabiting in these areas. Some of the prominent ones from west to east are the Monpa, Daffla, Abor, Mishmi, Nishi and the Nagas.Most of these communities practice Jhumming. It is also known as shifting or slash and Figure: Eastern Himalayas communities. Due to rugged topography, the inter-valley transportation linkages are nominal. Hence, most of the interactions are carried through the duar region along the Arunachal-Assamborder.
The Eastern Hills and Mountains
These are part of the Himalayan mountain system having their general alignment from the north to the south direction. They are known by different local names. In the north, they are known as Patkai Bum, Naga hills, the Manipur hills and in the south as Mizo or Lushai hills. These are low hills, inhabited by numerous tribal groups practicing Jhum cultivation.
Most of these ranges are separated from each other by numerous small rivers. The Barak is an important river in Manipur and Mizoram. The physiography ofManipur is unique by the presence of a large lake known as ‘Loktak’ lake at the centre, surrounded by mountains from all sides. Mzoram which is also known as the ‘Molassis basin’ which ismade up of soft unconsolidated deposits.Most of the rivers in Nagaland form the tributary of the Brahmaputra. While two rivers of Mizoram and Manipur are the tributaries of Barak river, which in turn is the tributary of Meghna; the rivers in the eastern part of Manipur are the tributaries of Chindwin, which in turn is a tributary of the Irrawaddy of Myanmar.
The Northern Palins
The northern plains are formed by the alluvial deposits brought by the rivers- the Indus, the Ganga and the Brahmaputra. These plain extend approximately 3,200 kmfromthe east to the west. The average width of these plains varies between 150-300 km. The maximum depth of alluvium deposits varies between 1,000-2,000 m. From the north to the south, these can be divided into three major zones: the Bhabar, the Tarai and the alluvial plains. The alluvial plains can be further divided into the Khadar and the Bhangar
Bhabar is a narrow belt ranging between 8-10 km parallel to the Shiwalik foothills at the break-up of the slope. As a result of this, the streams and rivers coming fromthe mountain deposit heavymaterials of rocks and boulders, and at times, disappear in this zone. South of the Bhabar is the Tarai belt, with an approximate width of 10-20 kmwhere most of the streams and rivers re-emerge without having any properly demarcated channel, thereby, creatingmarshy and swampy conditions known as the Taraiu. This has a luxurious growth of natural vegetation and houses a varied wild life.
The south of Tarai is a belt consisting of old and new alluvial deposits known as the Bhangar and Khadar respectively. These plains have characteristic features of mature stage of fluvial erosional and depositional landforms such as sand bars,meanders, oxbowlakes and braided channels. The Brahmaputra plains are known for their riverine islands and sand bars. Most of these areas are subjected to periodic floods and shifting river courses forming braided streams.
The mouths of these mighty rivers also form some of the largest deltas of the world, for example, the famous Sunderbans delta. Otherwise, this is a featureless plain with a general elevation of 50- 150 m above the mean sea level. The states of Haryana and Delhi form a water divide between the Indus and the Ganga river systems. As opposed to this, the Brahmaputra river flows from the northeast to the southwest direction before it takes an almost 90º southward turn at Dhubri before it enters into Bangladesh. These river valley plains have a fertile alluvial soil cover which supports a variety of crops like wheat, rice, sugarcane and jute, and hence, supports a large population.
The Peninsular Plateau
Rising from the height of 150 m above the river plains up to an elevation of 600-900 m is the irregular triangle known as the peninsular plateau. Delhi ridge in the northwest, (extension of Aravalis), the Rajmahal hills in the east, Gir range in the west and the Cardamom hills in the south constitute the outer extent of the peninsular plateau. However, an extension of this is also seen in the northeast, in the form of Shillong Karbi- Anglong plateau. The peninsular India is made up of a series of patland plateaus such as the Hazaribagh plateau, the Palamu plateau, the Ranchi plateau, theMalwa plateau, the Coimbatore plateau and the Karnataka plateau, etc. This is one of the oldest and the most stable landmass of India. The general elevation of the plateau is from the west to the east, which s also proved by the pattern of the flow of rivers. Name some rivers of the peninsular plateau which have their confluence in the Bay of Bengal and the Arabian sea andmention some landforms which are typical to the east flowing rivers but are absent in the west flowing rivers. Some of the important physiographic features of this region are tors, block mountains, rift valleys, spurs, bare rocky structures, series of hummocky hills and wall-like quartzite dykes offering natural sites for water storage. The western and northwestern part of the plateau has an emphatic presence of black soil.
This peninsular plateau has undergone recurrent phases of upliftment and submergence accompanied by crustal faulting and fractures. (The Bhima fault needs special mention, because of its recurrent seismic activities). These spatial variations have brought in elements of diversity in the relief of the peninsular plateau. The northwestern part of the plateau has a complex relief of ravines and gorges. The ravines of Chambal, Bhind and Morena are some of the wellknown examples.
On the basis of the prominent relief features, the peninsular plateau can be divided into three broad groups: (i) The Deccan Plateau (ii) The Central Highlands (iii) The Northeastern Plateau
The Deccan Plateau
This is bordered by the Western Ghats in the west, Eastern Ghats in the east and the Satpura,Maikal range and Mahadeo hills in the north. Western Ghats are locally known by different names such as Sahyadri in Maharashtra, Nilgiri hills in Karnataka and Tamil Nadu and Anaimalai hills and Cardamom hills in Kerala. Western Ghats are comparatively higher in elevation and more continuous than the Eastern Ghats. Their average elevation is about 1,500 m with the height increasing from north to south. ‘Anaimudi’ (2,695 m), the highest peak of Peninsular plateaus is located on the Anaimalai hills of the Western Ghats followed by Dodabetta (2,670m) on the Nilgiri hills. Most of the Peninsular rivers have their origin in the Western Ghats. Eastern Ghats comprising the discontinuous and low hills are highly eroded by the rivers such as the Mahanadi, the Godavari, the Krishna, the Kaveri, etc. Some of the important ranges include the Javadi hills, the Palconda range, the Nallamala hills, the Mahendragiri hills, etc. The Eastern and the Western Ghatsmeet each other at the Nilgiri hills.
The Central Highlands
They are bounded to the west by the Aravali range. The Satpura range is formed by a series of scarped plateaus on the south, generally at an elevation varying between 600-900 m above the mean sea level. This forms the northernmost boundary of the Deccan plateau. It is a classic example of the relict mountains which are highly denuded and form discontinuous ranges. The extension of the Peninsular plateau can be seen as far as Jaisalmer in the West, where it has been covered by the longitudinal sand ridges and crescent-shaped sand dunes called barchans. This region has undergone metamorphic processes in its geological history, which can be corroborated by the presence of metamorphic rocks such as marble, slate, gneiss, etc.
The general elevation of the Central Highlands ranges between 700-1,000 m above the mean sea level and it slopes towards the north and northeastern directions. Most of the tributaries of the river Yamuna have their origin in the Vindhyan and Kaimur ranges. Banas is the only significant tributary of the river Chambal that originates fromthe Aravalli in the west. An eastern extension of the Central Highland is formed by the Rajmahal hills, to the south of which lies a large reserve of mineral resources in the Chotanagpur plateau.
The Northeastern Plateau
In fact it is an extension of the main peninsular plateau, it is believed that due to the force exerted by the northeastward movement of the Indian plate at the time of the Himalayan origin, a huge fault was created between the Rajmahal hills and the Meghalaya plateau. Later, this depression got filled up by the deposition activity of the numerous rivers. Today, the Meghalaya and Karbi Anglong plateau stand detached from the main peninsular Block. The meghalaya plateau is further subdivided into three: (i) The Garo Hills; (ii) The Khasi Hills; (ii) The Jaintia Hills, named after the tribal groups inhabiting this region. An extension of this is also seen in the Karbi Anglong hills of Assam. Similar to the Chotanagpur plateau, the Meghalaya plateau is also rich in mineral resources like coal, iron ore, sillimanite, limestone and uranium. This area receives maximum rainfall from the south west monsoon. As a result, the Meghalaya plateau has a highly eroded surface. Cherrapunji displays a bare rocky surface devoid of any permanent vegetation cover.
The Indian Desert
To the northwest of the Aravali hills lies the Great Indian desert. It is a land of undulating topography dotted with longitudinal dunes and barchans. This region receives low rainfall below 150mmper year; hence, it has arid climate with low vegetation cover. It is because of these characteristic features that this is also known as Marusthali. It is believed that during the Mesozoic era, this region was under the sea. This can be corroborated by the evidence available at wood fossils park at Aakal and marine deposits around Brahmsar, near Jaisalmer (The approximate age of the wood fossils is estimated to be 180 million years). Though the underlying rock structure of the desert is an extension of the peninsular plateau, yet, due to extreme arid conditions, its surface features have been carved by physical weathering and wind actions. Some of the well pronounced desert land features present here aremushroomrocks, shifting dunes and oasis (mostly in its southern part). On the basis of the orientation, the desert can be divided into two parts: the northern part is sloping towards Sindh and the southern towards the Rann of Rachchh. Most of the rivers in this region are ephemeral. The Luni river flowing in the southern part of the desert is of some significance. Low precipitation and high evaporation makes it a water deficit region. There are some streams which disappear after flowing for some distance and present a typical case of inland drainage by joining a lake or playa. The lakes and the playas have brackish water which is the main source of obtaining sal
The Coastal Plains
India has a long coastline. On the basis of the location and active geomorphological processes, it can be divided into two: (i) the western coastal plains; (ii) the eastern coastal plains.
The western coastal plains are an example of submerged coastal plain. It is believed that the city of Dwaraka which was once a part of the Indian mainland situated along the west coast is submerged under water. Because of this submergence it is a narrow belt and provides natural conditions for the development of ports and harbours. Kandla, Mazagaon, JLN port Navha Sheva, Marmagao. Mangalore, Cochin, etc. are some of the important natural ports located along the west coast. Extending from the Gujarat coast in the north to the Kerala coast in the south, the western coast may be divided into following divisions- the Kachchh and Kathiawar coast in Gujarat, Konkan coast inMaharashtra. Goan coast and Malabar coast in Karnataka and Kerala respectively. The western coastal plains are narrow in the middle and get broader towards north and south. The rivers flowing through this coastal plain do not form any delta. The Malabar coast has got certain distinguishing features in the form of ‘Kayals’ (backwaters), which are used for fishing, inland navigation and also due to its special attraction for tourists. Every year the famous Nehru Trophy Vallamkali (boat race) is held in Punnamada Kayal in Kerala.
Some important mountain peaks in Andaman and Nicobar islands are Saddle peak (North Andaman- 738 m), Mount Diavolo (Middle Andaman- 515 m), Mount Koyob (South Andaman- 460m) andMount Thuiller (Great Nicobar- 642 m).
As compared to the western coastal plain, the eastern coastal plain is broader and is an example of an emergent coast. There are well developed deltas here, formed by the rivers flowing eastward in to the Bay of Bengal. These include the deltas of the Mahanadi, the Godavari, the Krishna and the Kaveri. Because of its emergent nature, it has less number of ports and harbours. The continental shelf extends up to 500 km into the sea, which makes it difficult for the development of good ports and harbours. Name some ports on the eastern coast.
There are two major island groups in India- one in the Bay of Bengal and the other in the Arabian. The Bay of Bengal Island groups consist of about 572 islands/islets. These are situated roughly between 6ºN – 14ºN and 92ºE-94ºE. The two principal groups of islets include the Ritchie’s archipelago and the Labrynth island. The entire group of island is divided into two broad categoriesthe Andaman in the north and the Nicobar in the south. They are separated by a water body which is called the Ten degree channel. It s believed that these islands are an elevated portion of submarine mountains. However, some smaller islands are volcanic in origin. Barren island, the only active volcano in India is also situated in the Nicobar islands.
The coastal line has some coral deposits, and beautiful beaches. These islands receive convectional rainfall and have an equatorial type of vegetation.
The islands of the Arabian sea include Lakshadweep and Minicoy. These are scattered between 8ºN and 71ºE- 74ºE longitude. These islands are located at a distance of 280 km- 480 km off the Kerala coast. The entire island group is built of coral deposits. There are approximately 36 islands of which 11 are inhabited. Minicoy is the largest island with an area of 453 sq. km. The entire group of islands is broadly divided by the Eleventh degree channel, north of which is the Amini Island and to the south of the Canannore Island. The islands of this archipelago have storm beaches consisting of unconsolidated pebbles, shingles, cobbles and boulders on the eastern seaboard.