NCERT Solutions for Class 7 Social Science Chapter 3 Climates of India (PDF) – 2027

India’s climate is diverse because the five factors that decide climate — latitude, altitude, distance from the sea, winds and topography — all vary greatly across the country.

India stretches from the warm south, close to the Equator, to the cold north. It has coasts at sea level and Himalayan peaks kilometres high; long coastlines and places deep inland; moist sea winds and dry desert winds; mountains, plateaus, plains and a desert. So one country has alpine, temperate, subtropical, arid, tropical wet, semi-arid and tropical climates.

Monsoons are seasonal winds over the Indian Ocean and the lands around it (from the Arabic mausim, ‘season’). In everyday use, ‘monsoon’ means the seasonal rains they bring.

How they form: land heats up and cools down faster than the ocean. In summer the hot land has low pressure, so moist winds blow from the high-pressure ocean to the land and bring heavy rain (southwest monsoon). In winter the cold land has high pressure, so dry winds blow from land to ocean (northeast monsoon).

Climate shapes our culture, economy and society.

• Culture: festivals, rituals, food, clothes and even music follow the seasons and the farming year — e.g. Bihu, Pongal, Onam, Baisakhi, Lohri; the rāga Meghamalhār.
• Economy: farming depends on climate (wheat in the northern plains, rice and spices on the west coast); industry needs water and predictable weather.
• Society: a ‘monsoon failure’ ruins crops, makes people (generally women) walk far for water, pushes labourers to migrate to cities and makes food costlier (inflation).

Understanding the climate tells us which disasters strike where and in which season, so we can prepare before they come.

• Cyclones hit the east coast every year: the IMD tracks them and tells where they will land, and the NDRF evacuates people in time.
• Floods and landslides come in the monsoon: we can clear drains, stop building on waterways and weak slopes, and plant trees.
• Forest fires come in dry, windy months: fire lines and watch-towers can be readied.

It also shows the need for environment-friendly practices and for building resilience in communities.

Climate change means significant, long-term changes in the climate — in temperature, precipitation and weather events — of the whole planet or of a region. Since the 19th century it has been caused mainly by human activities: burning fossil fuels, deforestation, harmful industrial practices and wasteful consumption. These release greenhouse gases that trap extra heat and cause global warming.

Consequences: extremes of weather and temperature; more severe floods, cyclones, glacial bursts and forest fires; disturbed patterns that plants, animals and people are adapted to; and losses to farming and industry — e.g. India’s short, mild winter of early 2025, when the average temperature was 1–3°C above normal.

Weather is what we experience from hour to hour or day to day — rain, sunshine, wind — and it keeps changing. Climate is the pattern of weather a region experiences over a long period, several decades at least, and it usually stays stable.

To both. The weather changes with the season — dry and hot in summer, humid and rainy in the monsoon. And the pattern of seasons a region has every year is part of its climate: for example, India has a rainy season (the monsoon) besides the four main seasons.

“My favourite season is varṣhā, the rainy season. After the hot, dusty summer, the first shower cools the air and fills it with the smell of wet earth. Fields and trees turn green, frogs call at night, and we enjoy hot pakoras and paper boats. I love the rains most because they fill our wells and bring the crops to life.”

(a group in Assam might record):

In many parts of India, trees such as sal, teak, palāsh (ṭesu) and semal shed their leaves in the cool, dry months, and the Indian almond turns red and yellow before its leaves fall.

Why: shedding leaves saves water. A tree keeps losing water through its leaves; when the soil is dry or cold it cannot replace this water, so it drops them. Before they fall, the green colour fades and yellow, orange and red colours show.

Many factors, working together, create different climates — some on the scale of the whole planet, others regional or local. The main ones are latitude, altitude, proximity to the sea, winds and topography. The climate of any region is decided by all of them together.

Because of the angle at which the sun’s rays strike the Earth. At the Equator the rays fall nearly perpendicular, so their energy is focused on a small area and heats it strongly. Towards the poles the rays are slanting (oblique): the same energy spreads over a larger area and passes through more of the atmosphere, which weakens it further. So places get cooler as latitude increases.

Temperature falls as altitude rises, for two reasons:

1. Air pressure, and so air density, decreases with height, and less dense air is cooler.
2. The sun heats the Earth’s surface, which warms the air above it; the farther a place is from the surface, the less warm the air.

So hill stations, being high above the plains, are cooler.

Because Ooty is much higher than Coimbatore. Both are at almost the same latitude, so latitude is not the cause. Ooty stands at about 2,200 m in the Nilgiri hills, while Coimbatore is on the plain at about 400 m. At Ooty’s height the air is thinner and farther from the heated ground, so it is cooler — its summer temperatures are about 13–15° lower.

The water cycle: water from the oceans and the Earth’s surface evaporates into the air as vapour; winds carry this moist air over the land; there it cools and condenses into clouds, and the water returns as rain, hail or snow.

That is why winds coming from the sea can bring rain, while winds that have crossed deserts are dry.

Mawsynram in Meghalaya gets about 11,000 mm (11 m) of rain a year — the highest average in the world, roughly 9 times India’s average of about 1,200 mm. Moist monsoon winds from the Bay of Bengal are forced to rise sharply by the Khasi Hills; the rising air cools and drops its moisture as heavy rain. This is topography at work.

The monsoon is so important in Indian life that it inspired classical music. Meghamalhār (Hindustani; megha = cloud) and amruthavarshini (Carnatic; ‘she who showers nectar’) are rāgas linked with clouds and rain.

— local signs of weather:

• Ants carrying their eggs to higher ground → heavy rain in a day or two.
• Peacocks calling and dancing → the monsoon is near.
• Dragonflies and swallows flying very low → rain the same evening.
• A ring (halo) round the moon → rain in two or three days.
• Thick fog over the fields on a winter morning → a clear, dry day.

— one elder’s account, written up:

For the cultural fest, form teams for dance, songs, food and a display board of the elders’ stories, and invite the elders as guests.

The NDRF is a force specially trained for rescue and relief in both natural and human-made disasters. Its battalions are placed at 12 locations across India so that help can reach any disaster quickly. Together with IMD warnings, it can evacuate people before a cyclone strikes — prediction plus preparation saves lives.

Cyclones form over the sea when a strong low-pressure system develops.

1. In some situations the air pressure near the sea becomes lower than in the surrounding areas.
2. Air from the surroundings, especially moist air from the sea, moves into this low-pressure area, bringing moisture and rain.
3. If the low pressure is intense and the winds are very fast, a cyclone forms.
4. The winds form clouds and rotate inwards around the centre; this calm, cloudless centre is the ‘eye of the cyclone’.

Clouds are made of water — masses of tiny water droplets, ice crystals, or a mixture of both, suspended (floating) in the atmosphere. They form when moist air rises and cools, and the invisible water vapour condenses into droplets so small that rising air keeps them afloat. Clouds are not water vapour itself, which is invisible.

These states flood because they are low, flat river plains or heavy-rain coasts:

• Assam — the narrow Brahmaputra valley gets very heavy rain and Himalayan snow-melt; the silt-laden river overflows.
• Bihar and Uttar Pradesh — the flat Ganga plains; rivers such as the Kosi come down from the Himalayas, slow down, drop silt and spill over.
• Kerala — the Western Ghats cause very heavy monsoon rain on a narrow coast.
• Andhra Pradesh — the low, flat Krishna and Godavari deltas, often hit by cyclones.

This event shows how heavy rain, a glacial burst and landslides can combine into a disaster. Several days of continuous heavy rain in 2013 caused a sudden glacial burst in Uttarakhand; landslides and floods followed, destroying the area around the Kedarnath temple, villages, roads and bridges. About 6,000 people, many of them pilgrims, died — which is why understanding the climate and preparing for disasters matters.

Fig. 3.15 shows a cyclone, a landslide, a forest fire and a flood. Sample answer on their effects:

— the trigger is usually natural, but human actions make the damage worse:

— preventive measures:

• Cyclones: early warnings, cyclone shelters, evacuation drills, protecting mangroves.
• Floods: clean drains, no building on waterways, embankments, rainwater harvesting.
• Landslides: approved construction methods, trees on slopes, keeping natural water channels open.
• Forest fires: fire lines and watch-towers before the dry season; never leaving fires or cigarettes in a forest.

Against all four: cut greenhouse gases and plant more trees.

Burning fossil fuels (coal, petroleum oil, natural gas) releases huge amounts of carbon dioxide and other greenhouse gases, which trap the Sun’s heat. Naturally, these gases keep the Earth just warm enough for life. But humans have added enormous amounts in just a few centuries, so extra heat is trapped. This causes rapid global warming, which disturbs the climate patterns that plants, animals and people are adapted to.

India’s landforms shape its climate. The Himalayas give alpine and temperate climates and shield India from cold Central Asian winds; the Western Ghats bring heavy rain to the west coast but less to the Deccan Plateau (semi-arid); the flat Thar Desert is arid; the northern plains are subtropical; and the coasts are tropical, with temperatures moderated by the sea.

Weather changes from hour to hour and day to day; seasons last a few months and come back every year; climate is the long-term pattern of weather in a region over several decades (three or more).

Five factors decide a region’s climate:

• Latitude — places near the Equator are hot; places far from it are cooler.
• Altitude — higher places are cooler.
• Proximity to the sea — the sea keeps temperatures moderate.
• Winds — they bring heat, cold or moisture.
• Topography — mountains block winds or make them rise and give rain.

Most of India’s rain comes in the monsoon months, so farming depends on the monsoon. It fills the rivers and soaks the soil, and sowing follows its arrival (early June in the south, the whole country by mid-July). A good monsoon means good harvests and work; a ‘monsoon failure’ means crop loss, water shortage, migration to cities and costlier food.

Climate decides which crops grow, and the farming year decides when many festivals are held. Festivals such as Baisakhi, Pongal, Onam, Bihu and Lohri mark sowing, the rains or the harvest, and the monsoon has even inspired rāgas. Economic activity — farming and industry — also depends on rain, water and predictable weather.

If we know which disasters strike where and when, we can prepare in advance. The IMD tracks cyclones and warns people, and the NDRF evacuates them; flood-prone areas can keep drains clear and avoid building on waterways; warning systems give people time to move to safety. This reduces the loss of life and property.

Climate change makes weather and temperature more extreme — hotter and shorter winters, heavier rain and longer dry spells, faster-melting glaciers and stronger storms. This harms the natural world (plants, animals, glaciers, coral reefs) and the human world (crops, homes, health, industry). Governments try to slow it through mitigation: cutting greenhouse gases, planting trees and using renewable energy.

Weather is what we experience every hour or day — it might be raining, or there could be bright sunshine, a lot of wind. The weather keeps changing.

Climate is the pattern of weather an area or region experiences over a long period of time — several decades at least. This pattern varies from region to region, and it usually remains stable.

Because the sea acts as a moderator of temperature. Water heats up and cools down more slowly than land. In summer the sea stays cooler than the land, so sea air cools the coast; in winter the sea stays warmer, so sea air warms the coast. So coastal places have mild summers and winters. For example, Mumbai’s range is about 14°C (32°C to 18°C), but inland Nagpur’s is 34°C (44°C to 10°C).

The monsoon winds control India’s climate, especially its rainfall and seasons.

• In summer the southwest monsoon brings moist winds from the ocean and gives India most of its rain, creating a distinct rainy season.
• In winter the winds reverse: the dry northeast monsoon brings cool, dry weather, but after crossing the Bay of Bengal it gives rain to parts of east and south India.
• With the Western Ghats, they make the west coast very wet and the Deccan Plateau much drier.

Chennai is at a low latitude, near sea level and on the coast; Leh is far to the north, very high in the Himalayas (about 3,500 m) and far from the sea. At Chennai the sun’s rays fall nearly perpendicular all year and the sea keeps temperatures even, so it stays warm. At Leh the thin air of high altitude and the more slanting rays keep it cold, and with no sea nearby its winters are very severe.

Draw two outline maps of India side by side, as in Fig. 3.9:

• A. Summer (southwest monsoon): LOW pressure over the land, HIGH over the seas; arrows from the Arabian Sea and the Bay of Bengal on to the land; label ‘moist winds — heavy rain’.
• B. Winter (northeast monsoon): HIGH pressure over the land, LOW over the seas; arrows from the land out to the sea; label ‘dry winds’, with one arrow crossing the Bay of Bengal to bring rain to the Tamil Nadu coast.

— festivals for the poster (add a picture or drawing of each):

Caption for the poster: “Every festival here marks a moment in the farming year — sowing, the rains or the harvest.”

28 May — The amaltās near our well is in full bloom and the ants are carrying their eggs uphill, so the rain must be near. Today I finished ploughing and levelling the field and repaired the broken bund, so the rain will not wash the soil away. I cleaned the channel to our tank. The seeds are bought and stored dry with neem leaves. I will sow only after the rain settles, not at the first shower. May the monsoon come on time!

Sample answer — Floods

A flood occurs when water overflows on to normally dry land. Causes: heavy monsoon rain, rivers overflowing their banks and glacial lakes bursting; human actions make it worse — cutting forests, building on waterways, blocked drains and concrete surfaces that do not absorb water. Impacts: loss of lives, homes, crops and cattle; roads and bridges destroyed; disease spreads and food prices rise. Actions: individuals can keep drains free of plastic and follow warnings; communities can clean drains, revive ponds and plant trees; the government can give early warnings, build embankments, stop building on rivers and keep the NDRF ready.