NCERT Solutions Exploring Society: India and Beyond Chapter 3 A satellite view of the Ganga plain (Fig. 3.9) — LET'S EXPLORE
Book page 54 Updated on2026-09-05
Q1.
Which colour is the Ganga plain?
Answer
The Ganga plain is the broad green band that runs across the middle of the picture from left to right, just below the mountains.
The green is vegetation — mostly crops. The plain is one huge stretch of cultivated fields, so from a satellite it reads as continuous green.
Look closely and you can trace pale silvery lines winding through the green: those are the Ganga and its tributaries, with their wide sandy beds.
Towards the right (east), the green fades into a hazy grey-white sheet. That is smog and mist hanging over the lower Ganga plain — a reminder of the pollution the chapter mentions.
Why green means fertile here: the rivers bring sediments — particles of rock, sand and silt — down from the Himalayas and drop them on the plain. That deposited soil is deep, soft and rich, so almost every square kilometre can be farmed. Colour on a satellite image is really a report on the soil beneath.
Q2.
What does the white expanse represent?
Answer
The white expanse across the top and top-right of the image is snow and ice on the Himalayas and the Tibetan Plateau, mixed with some cloud.
Part of the white area
What it is
The sharp, ridged white line along the top of the green plain
The high Himalayan range under permanent snow — you can even see the dark shadowed valleys between the ridges
The broad, softer white sheet beyond it, at the top right
The snow-covered Tibetan Plateau, together with clouds sitting over it
Small dark blue patches inside the white
High-altitude lakes on the plateau
Why it is white all year: at those altitudes the air is so cold that the snow may never melt, leaving the mountains permanently snow-capped (page 43). Lower down, the snow melts every summer — and that melt-water is what feeds the rivers running through the green plain just below.
Look for the boundary: the white and the green meet along a remarkably sharp line. That line is where the mountains end and the plain begins — one of the clearest natural borders on the Earth, and you can see it from space.
Q3.
What does the brown expanse at the bottom left of the image represent?
Answer
The brown and sandy-tan expanse on the lower left is dry land with very little vegetation — the Thar Desert region of Rajasthan and the bare, rocky uplands south and east of it.
Brown from space means bare soil, sand or rock showing through, because there are few plants to cover it.
This part of north-west India gets very little rainfall, so it cannot support the continuous crop cover that makes the Ganga plain green.
Further down, the brown becomes patchy and reddish — that is the drier, stonier country of the central Indian uplands, where thin soil sits directly on rock.
Colour in Fig. 3.9
What it shows
Why
Green
The Ganga plain
Deep fertile soil from river sediments, plenty of water — continuous crops
White
The Himalayas and Tibetan Plateau
Snow and ice, plus cloud, at very high altitude
Brown / sandy
The dry lands of the north-west
Very little precipitation, so bare sand and rock instead of plants
The whole lesson in one picture: three landforms and three climates lie side by side in a single frame — snow-white mountains, a green fertile plain and a brown dry expanse. The colours are not decoration; each one is telling you how much water reaches that land and what kind of life it can support.