Q1.
Notice the concentration of lighting in the plains. What could be the reason for this concentration?
Answer
Looking at Fig. 1.16, the lights are packed into a broad band that follows the Northern Plains, while the Himalayas above and the plateau below are much darker. Lights at night mark people. So the picture is really a map of where India's population is densest.
Why so many people live there:
- Fertile soil. The Ganga, Indus, Brahmaputra and their tributaries bring down minerals from the Himalayas and spread them over the plains, making the land ideal for farming.
- Water all year. These are perennial rivers, so drinking water and irrigation never fail completely.
- Flat land. It is easy to build on, and it allowed an elaborate road and railway network — so towns and cities grew and joined up.
- A long history. These plains have been the heart of India's civilisation for thousands of years, so the settlements are old and large.
Why it happens: more people means more homes, streets, markets, factories and highways — and every one of them is lit. Mountains and deserts have few people and therefore few lights, so on a night-time satellite image the geography of India draws itself.
Try this: look closely and you can even see bright lines joining the bright dots. Those are lit highways and the strings of towns along them.