Class 7 Social Science Chapter 1: Geographical Diversity of India

A wall along the north

Look at the top of a physical map of India. A long band of brown and white runs right across it.

That is the Himalayan range. It stretches about 2,500 km, and it shuts India off from the rest of Asia like a wall.

The name says what it is

The word Himalaya is built from two Sanskrit words. Hima means snow, and alaya means a dwelling or abode.

So the name means the abode of snow. Many of its peaks rise above 8,000 metres, and those are known together as the Eight Thousanders.

Not only ours

The range does not sit inside one country. It runs through six: India, Nepal, Bhutan, China, Pakistan and Afghanistan.

So a mountain wall that feels like India’s northern edge is shared with five neighbours.

The water tower

In summer the snow melts, and that meltwater feeds the Ganga, the Indus and the Brahmaputra.

Those rivers and their tributaries supply drinking water, irrigation and industry for hundreds of millions of people. That is why the range is nicknamed the Water Tower of Asia.

Once joined to Africa

The Himalayas have not always been there, and the story of how they arrived is worth knowing. India was once part of a much larger landmass called Gondwana.

Its neighbour there was Africa. India broke away and began drifting northwards.

A collision in slow motion

About 50 million years ago India reached Eurasia and ran into it. Land caught between the two had nowhere to go but up.

It buckled and folded upwards, the way a carpet wrinkles when you push one end of it across the floor. The folds are the mountains.

Still happening

That collision has not finished. India is still pressing northwards at about 5 centimetres a year, which is slower than hair grows.

So the range is still rising, by roughly 5 millimetres a year. That sounds like nothing, but over a thousand years it adds about 5 metres.

Three ranges, not one

The Himalayas are not a single ridge. They are usually described as three ranges lying one behind the other.

Each has its own height, its own climate and its own way of life, so it is worth taking them in order from the north.

The Himadri

The Himadri, or Greater Himalayas, is the northernmost and the highest. Mount Everest and Kanchenjunga stand here.

It stays under snow all year round. Life is hard at that altitude, and there are few settlements.

The Himachal

South of it lies the Himachal, or Lower Himalayas. It is lower, so it is milder.

That milder climate supports rich wildlife and plenty of people. The hill stations are here: Nainital and Mussoorie in Uttarakhand, Darjeeling in West Bengal, and Shimla in Himachal Pradesh.

The Shivalik Hills

The Shivalik Hills, or Outer Himalayas, are the lowest and the furthest south. They are rolling hills under dense forest.

They are rich in wildlife, and they act as a step down between the mountains and the plains below.

Building for the mountains

People here build for the conditions. In the western Himalayas the kath-kuni, also called dhajji-dewari, style uses local stone and wood together.

The result keeps a house warm, and the timber lets the walls flex rather than crack in a mild earthquake.

A desert that is cold

Say desert and most people picture heat. India has a cold one.

Ladakh is a cold desert. Winter temperatures there drop below -30 degrees Celsius, and very little rain falls.

Moonland

The ground in Ladakh is rocky and bare, cut by deep valleys. People call it moonland, because it looks like the surface of the moon.

Those rocks are largely sand and clay, because this folded land was once part of an ocean floor. Wind and rain have since carved it into the shapes you see.

Life in the cold desert

Harsh as it is, Ladakh is not empty. Snow leopards, ibex and Tibetan antelopes live there.

It also has Pangong Tso, a lake whose water is salty rather than fresh, because minerals wash into it from the mountains around. Tso simply means lake.

What carries forward

The Himalayas run about 2,500 km through six countries, carry peaks above 8,000 metres, and feed the Ganga, Indus and Brahmaputra, which earns them the name Water Tower of Asia. They exist because India broke from Gondwana, drifted north and collided with Eurasia about 50 million years ago, folding the land between.

The collision continues, so the range still rises about 5 millimetres a year. It is made of three ranges: the snow-covered Himadri, the milder Himachal with its hill stations, and the forested Shivalik Hills. Ladakh, within the mountains, is a cold desert where winter falls below -30 degrees Celsius.

Scenario:

A school is planning a week in the Himalayas and the class is arguing about where to go. One pupil wants the Himadri, because that is where Mount Everest and Kanchenjunga are, and says the group can simply stay in a village there. Another has read that Ladakh is a desert and has packed only light summer clothes. A third asks why the mountains are there at all, and whether they are finished growing. The teacher asks the class to settle all three questions from the geography before any booking is made.

Analysis:

Three questions, and the chapter answers each of them.

Activity:

Find the three ranges on a physical map and list the states each one passes through.

Title:

Push a carpet, make a mountain

Safety:

Push slowly so nobody slips on the rug.

What You Notice:

The rug buckles upwards into folds exactly where the two forces meet, which is what happened to the land between India and Eurasia. The hand travels much further than the fold is tall, which matches 5 centimetres of movement against 5 millimetres of height. A thousand years of that is about 5 metres.

India once lay beside Africa, in a landmass called Gondwana, before it drifted north to build the Himalayas.

The range is still growing about 5 millimetres a year, which is roughly 5 metres every thousand years.

Ladakh is called moonland because its bare rocky ground resembles the surface of the moon.

Hima is snow, alaya is home.

India moves centimetres, the mountains gain millimetres.

Down from the mountains

Come south off the Himalayas and the land flattens out completely. These are the Gangetic Plains, also called the Northern Plains.

They are vast, and they are fertile. A large share of India’s population lives on them.

Why the soil is so good

The rivers are the reason. The Ganga, the Indus and the Brahmaputra systems cross the plains with a wide network of tributaries.

They carry minerals down from the mountains and spread them over the land. That is what makes the soil rich enough for abundant farming.

More than farming

Water from these rivers is not used for crops alone. It is also used to generate electricity.

And because the land is flat, roads and railways run easily across it. The rivers themselves have carried people and trade for thousands of years.

A river with a different name

Most Indian rivers carry the names of goddesses. The Ganga, the Yamuna and the Kaveri all do.

The Brahmaputra is the exception. Its name means the son of Brahma, and unlike most rivers it swells in summer rather than shrinking, because that is when the mountain snow melts.

West to the Thar

Move west on the map and the colour turns yellow. This is the Great Indian Desert, better known as the Thar.

It is a vast arid region, and most of it lies inside India. It spreads across Rajasthan, Gujarat, Punjab and Haryana.

How a dune is built

The dunes are made by wind. Moving air shifts loose sand and piles it into hills.

Some of those dunes rise as high as 150 metres. Unlike a rock mountain, a dune has no fixed shape, because the wind keeps rebuilding it.

A desert is a barrier

The Thar separates as much as it covers. Daytime temperatures are very high, nights are cold, and water is hard to find.

Those conditions discourage people and animals from crossing, so the desert has long acted as a natural barrier.

Living with very little water

People here have shaped their lives around what the land gives. Food, clothing and daily habits are all suited to the heat and the dryness.

Water is precious enough that utensils are scoured clean with sand, and only a little is used to rinse them. Even that rinse water is kept and used again, often on a plant.

Catching the rain

Rajasthan is known for clever ways of saving water. The taanka, also called a kund, is one of them.

It is a structure built to collect rainwater and store it, often for drinking. In a place with so little rain, catching what falls matters more than finding a well.

East again, to very old hills

Trace east from the Thar and you meet the Aravalli Hills. They are among the oldest mountains anywhere in the world.

Their age is about 2.5 billion years. Compare that with the Himalayas, which began only about 50 million years ago, and the difference is enormous.

Worn down by time

Age shows in their height. Mount Abu, the highest peak, rises above 1,700 metres, but most Aravalli hills stand between 300 and 900 metres.

The range runs through Delhi, Rajasthan, Haryana and Gujarat. A drive of about four and a half hours takes you from Mount Abu to Jodhpur, and from one kind of country into an entirely different one.

The barrier against the barrier

The Aravallis do an important job. They stand in the way of the Thar Desert and stop it spreading further east.

So the region has two barriers working at right angles to each other. The desert blocks movement, and the hills block the desert.

Minerals, and a first in the world

The Aravallis are rich in minerals, among them marble, granite, zinc and copper. Mining and construction have drawn on them for centuries.

The ancient mines at Zawar carry remarkable evidence. More than eight hundred years ago, the people working them led the world in mastering a difficult method of obtaining zinc.

Three landscapes, one lesson

Set the three side by side. The plains are flat, watered and crowded; the desert is dry, hot by day, cold by night and thinly peopled; the hills are old, worn and full of minerals.

In each case the land sets the terms and people answer them. That is the pattern worth carrying into the rest of the chapter.

What carries forward

The Gangetic Plains are fertile because Himalayan rivers spread minerals across them, and their flatness carries roads, railways and a large part of India’s population. The Thar is arid, spans four states, builds dunes up to 150 metres, and acts as a barrier, so life there is organised around saving water, with taanka or kund structures to catch rain.

The Aravallis are about 2.5 billion years old, worn down to mostly 300 to 900 metres with Mount Abu above 1,700, and they hold back the Thar from moving east. Their minerals include zinc, and the Zawar mines show Indians mastering zinc first in the world over eight centuries ago.

Scenario:

A family moves from Jodhpur to a town on the Gangetic Plains. Jodhpur sits at the edge of the Thar. The children are astonished that water runs from the tap all day. The eldest says their grandmother scoured pots with sand, and that this was simply old-fashioned. Their father points out the drive home. It passes Mount Abu in the Aravallis in about four and a half hours. The country there looks nothing like either place. A neighbour adds that the low Aravalli hills cannot matter much to anybody.

Analysis:

Three remarks about three landscapes, and the geography answers all of them.

Activity:

Measure how much water your household uses washing up for one day, then try the sand-scouring method on one pot and compare.

Title:

Build a dune, then stop it

Safety:

Keep your face to one side so blown sand does not reach your eyes.

What You Notice:

The wind piles sand into a hill-like dune and keeps rebuilding it, which is why a dune has no fixed shape. The line of stones holds the sand back, which is exactly the job the Aravallis do for the Thar.

The Aravallis are about fifty times older than the Himalayas, and a great deal lower, because time wears a range down.

The rinse water from washing up in the Thar is commonly saved and poured on a plant rather than thrown away.

At the Zawar mines, over eight centuries ago, the miners there led the world in obtaining zinc.

Rivers carry the soil, wind carries the sand.

Old hills are low hills.

What a plateau is

A plateau is land that rises above the country around it and then flattens out on top. Its sides are often steep.

India has several. The most important is the large triangular block that fills the middle and south of the country.

Why it is called peninsular

A peninsula is land with water on three sides of it. This block has the Arabian Sea to its west, the Bay of Bengal to its east and the Indian Ocean to its south.

So it is called the Peninsular Plateau. Like the Aravallis, it is a very old formation.

Two walls of hills

The plateau is edged by two ranges. The Western Ghats run down the west coast, and the Eastern Ghats down the east.

They are not matched. Taller of the two, the Western Ghats hold one unbroken line; their eastern counterpart stands lower and breaks into scattered hills.

The Western Ghats

In the monsoon, waterfalls pour down the steep western sides. The range is a UNESCO World Heritage Site, and it holds many rivers and a great variety of living things.

Its northern part has a name of its own: the Sahyadri Hills.

The Deccan

Between the two ranges lies the Deccan Plateau. It is a wide stretch of flat highland.

It is rich in minerals, in forest and in fertile land, which makes it important to India’s economy.

One tilt explains the rivers

Here is the detail that ties the region together. The plateau is not level. It tilts slightly towards the east.

Water runs downhill, so most of its rivers run east. The Godavari, the Krishna and the Mahanadi all cross the country to reach the Bay of Bengal.

The two that go west

Two well-known rivers do the opposite. The Narmada and the Tapti flow west instead, and drain into the Arabian Sea.

Once you know about the tilt, you do not have to memorise which river goes where. You can reason it out, and then learn the exceptions.

What the rivers do

These rivers matter far beyond their banks. They water farms, supply industry, and drive hydroelectric power.

The plateau’s waterfalls do similar work. They draw visitors, generate electricity and feed irrigation.

The people of the forests

Dense forest still covers much of the plateau, and tribal communities live in it. They include the Korku and the Bhil, the Baiga, the Gond and the Santhal.

Each has its own language, its own traditions and a way of life closely tied to the natural world around it.

Round the edge

Now follow the outline of the country. India’s coastline runs over 7,500 km.

It is not one kind of place. There are golden beaches and black rocks, cliffs and thick green forest.

The West Coast

The West Coast runs from Gujarat down to Kerala, through Maharashtra, Goa and Karnataka. Most of its rivers rise in the Western Ghats close by.

Because the distance to the sea is short, they run fast. The shore is cut into coves and creeks, and its two widest river mouths belong to the Tapti and the Narmada.

Why the west has ports

Those creeks and estuaries make natural shelter for ships. The west coast carries many important ports and cities.

They have been centres of trade and economic life for thousands of years.

The East Coast

The East Coast is the strip caught between the Eastern Ghats inland and the open water. It reaches from the Ganga delta down to Kanyakumari.

Its plains are wide, and it carries the great river deltas: the Mahanadi, the Godavari, the Krishna and the Kaveri.

What a delta is

A delta forms where a river meets a larger body of water and drops the sediment it was carrying. Over time that sediment piles up.

The shape it builds is triangular, or spread out like a fan. Delta soil is superb for farming.

Lakes and a lagoon

The east coast also holds notable water bodies. Chilika Lake and Pulicat Lake are the two to know.

Pulicat is a lagoon, which means a body of water cut off from a larger one by a natural barrier.

What carries forward

The Peninsular Plateau is an old triangular highland with sea on three sides, edged by the taller continuous Western Ghats and the lower broken Eastern Ghats, with the Deccan between them. It tilts east, which is why the Godavari, Krishna and Mahanadi flow to the Bay of Bengal while the Narmada and Tapti flow west to the Arabian Sea.

India’s coastline runs over 7,500 km. The west coast has short swift rivers, coves, creeks and ports; the east coast has wide plains and great deltas, where rivers drop sediment into fan-shaped land that farms well.

Scenario:

A shipping company is comparing India’s coasts. Its manager notices that the west coast has many old ports. The east coast has fewer, but far more farmland near the shore. A trainee is puzzled by a map. She sees that the Godavari starts quite near the western side of the country, yet travels right across it to reach the Bay of Bengal. She asks why it does not simply take the short route west. Another trainee insists the two Ghats must be mirror images of each other.

Analysis:

Three observations about the peninsula, each with a geographical answer.

Activity:

On a physical map, trace one east-flowing and one west-flowing river and measure which travels further.

Title:

Tilt a tray and watch the water

Safety:

Keep the cloth to hand; water on the floor is slippery.

What You Notice:

Once the tray tilts, water always runs to the lower side, however far that is. That is the plateau tilting east. Water poured right at the raised rim can still run off the near edge, which is what the Narmada and Tapti do.

The Godavari begins near the western side of the country yet crosses the whole of it eastwards, because the plateau tilts that way.

The northern part of the Western Ghats has its own name, the Sahyadri Hills.

Pulicat Lake is a lagoon, which means a natural barrier separates it from the open sea.

The land leans east, so the rivers go east.

Delta is land, lagoon is water.

Out to the islands

India does not end at the mainland shore. Islands belonging to it are scattered away west in the Arabian Sea, away east in the Bay, and out in the wider ocean.

There are two major groups. Lakshadweep lies westward, in the Arabian Sea; the Andaman and Nicobar Islands lie eastward, out in the Bay.

A word worth knowing

A group of islands is called an archipelago. Both of India’s island groups are archipelagos.

Between them they offer unusual wildlife, fine beaches, coral reefs and even volcanoes. People have lived on some of them for tens of thousands of years.

Lakshadweep

Lakshadweep sits west of the mainland, off the Malabar coast of Kerala. Thirty-six islands make it up.

Those islands are built of coral, not of rock thrown up by a volcano. Not all of them have people living on them.

Why a few small islands matter

It is tempting to dismiss 36 small islands as unimportant. That would be a mistake.

Because they are Indian, India controls a vast area of sea around them. That allows fishing, the search for resources, and the protection of the environment there.

The Andaman and Nicobar Islands

This group is far larger in number. It has more than 500 islands, large and small, and they are volcanic.

They fall into two distinct sets, the Andaman Islands and the Nicobar Islands.

Outposts on the ocean

Their position is what makes them valuable. They sit far out in the Bay of Bengal, so they work as outposts, keeping watch over the ocean.

They also carry a wide variety of plants and animals.

A place to remember

The Andamans matter in history as well as geography. Many of India’s freedom fighters were imprisoned there, in a prison complex called the Cellular Jail, under extremely severe conditions.

It has been preserved rather than pulled down. It stands as a reminder of what those people gave up so that others could be free.

India’s only active volcano

One of these islands is unlike anything on the mainland. Barren Island, in the Andaman and Nicobar group, holds the only active volcano in India.

It still erupts from time to time, sending smoke and lava into the sky.

Back to the delta

Travel back from the islands across the Bay of Bengal and you reach the Sundarbans. They lie in the delta built by the Ganga, the Brahmaputra and their tributaries.

This is an unusual place because three things meet in it: the river, the sea and the land.

Shared with a neighbour

The Sundarbans do not belong to India alone. About half lie in India and the rest in Bangladesh.

They are a UNESCO Heritage site, and they are home to many species. The most famous is the Royal Bengal Tiger.

The hills of the Northeast

Now move east, to the last corner of the map. The Garo, Khasi and Jantia hills stand there.

They are known for thick greenery, very heavy rain and spectacular waterfalls.

Among the wettest places on Earth

This region receives one of the heaviest rainfalls found anywhere. That is not a small distinction.

All that water makes the region rich in forest, in unusual wildlife and in fertile land.

Living with the rain

People here have answered the rain with invention. In Meghalaya, bridges are grown rather than built, by training the living roots of trees across a stream.

A root bridge keeps growing stronger instead of rotting away, which is exactly what a timber bridge would do in that much rain.

A village and a festival

Mawlynnong, a village in Meghalaya, is known for how clean it is kept. The Khasi people also celebrate a festival called Shad Suk Mynsiem.

Both are reminders that geography and culture are not separate subjects. How people live follows from where they live.

The edges are not leftovers

Look back along the journey. The mainland has mountains, plains, a desert, old hills, a plateau and two coasts.

The edges add what the middle cannot: a vast sea area, a watch over the ocean, a tiger forest shared with a neighbour, and some of the heaviest rain anywhere.

What carries forward

India’s islands form two archipelagos: Lakshadweep, 36 coral islands in the Arabian Sea near Kerala, and the Andaman and Nicobar group, more than 500 volcanic islands in the Bay of Bengal, which act as ocean outposts and hold the Cellular Jail and Barren Island, India’s only active volcano.

The Sundarbans lie in the Ganga and Brahmaputra delta where river, sea and land meet, about half in India and half in Bangladesh, and are home to the Royal Bengal Tiger. The Garo, Khasi and Jantia hills of the Northeast receive one of the world’s highest rainfalls, and people there grow bridges from living roots.

Scenario:

A class is looking at a map of India and the surrounding seas. One pupil says the island groups are too small to matter. She argues they should simply be ignored in any account of the country. Another says both groups must be coral islands, since both lie in warm water and both have reefs in the photographs. A third traces the outline of the Sundarbans with a finger and announces that the whole forest is Indian. Their teacher does not correct anyone straight away. Instead she asks the class to test each claim against the chapter before anybody writes it down.

Analysis:

Three guesses from one map, and the chapter corrects all three.

Activity:

On a map, mark both island groups and shade the sea area that lies nearer to them than to any other country.

Title:

Grow a bridge, and test the rain

Safety:

Wash your hands after handling wet soil.

What You Notice:

The dry twig bridge softens and weakens as it stays wet, while the planted twigs stay firm and may even sprout. That is the reasoning behind a living root bridge: it answers heavy rain by growing instead of rotting.

India’s only active volcano is on Barren Island, in the Andaman and Nicobar group, and it still erupts.

The Sundarbans do not stop at the border: about half of the forest lies in Bangladesh.

In Meghalaya some bridges are grown from the living roots of trees, and they strengthen with age.

Lakshadweep is coral, the Andamans are volcanic.

Grow the bridge, do not build it.