Population | Social Science (Geography) Grade 9 CBSE

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The language of population

Population study has its own vocabulary. Tap each term to see what it means and how the ideas — size, density, growth and quality — connect.

Explore · Key population termstap a term

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The three big ideas

Population — the total number of people living in an area. It is the starting point for all planning, because every school, hospital and job has to serve real people.
Distribution — how people are spread across the land. In India this is very uneven: some regions are packed, others nearly empty.
Population density — the number of people per square kilometre. It tells you how crowded an area is.
Why it is uneven — flat, fertile river plains with water and good soil attract crowds; deserts, high mountains and dense forests stay thinly populated. Climate, water, soil and jobs all shape where people settle.

Population change — the change in the number of people over time. It happens through three things: births, deaths and migration.
Birth rate — the number of births per 1,000 people in a year. Death rate — the number of deaths per 1,000 people in a year.
Natural increase — the birth rate minus the death rate. When births clearly outnumber deaths, the population grows.
Migration — the movement of people from one place to another (for example, from villages to cities). It can raise or lower a region’s population without changing the country’s total.

Worked example. Why did India’s population grow rapidly after independence?

Step 1 — the death rate fell. Better healthcare, vaccines, cleaner water and more food made the death rate drop sharply.

Step 2 — the birth rate stayed high. For a long time families still had many children, so the birth rate came down only slowly.

Step 3 — a large gap. With far more births than deaths each year, the natural increase was big — so the population grew rapidly.

Common mistake: a falling birth rate does not automatically mean the population is shrinking. As long as births outnumber deaths, the population keeps growing — growth only slows once the birth rate and death rate get close to each other.

Age composition — the share of people in different age groups: children, working-age adults (about 15–59) and the elderly. It tells a country how many workers it has and how many people depend on them.
Sex ratio — the number of females per 1,000 males. It shows how balanced a society is.
Literacy — the share of people who can read and write. Along with health, it describes the quality of a population.
A healthy, literate and skilled population is a country’s greatest resource — it shapes the nation’s future far more than mere numbers do.

Where you'll meet it

Population, at work

Planning schools & hospitals

Knowing how many children and elderly people live in an area, and how fast the population is growing, lets governments decide where to build schools, clinics and hospitals — and how many teachers and doctors to train.

Planning jobs & resources

The size of the working-age group tells planners how many jobs are needed, while the total population shapes the demand for food, water, housing and electricity. Population data turns guesses into real planning.

Check yourself

Competency quiz

Modelled on the competency-based pattern — MCQ, assertion–reason and a case study, testing whether you can use the ideas, not just recall them.

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