Population Size and Density
If a class has 40 students and another class of the same size has 80, the second feels more crowded. To measure the crowding of countries we use population density.
Population density is the average number of people living per square kilometre. Density = total population ÷ area (sq km).
Key idea 1 : Population of India — As per the textbook India’s population was about 121 crore in Census 2011 and India is the second most populous country in the world. India has only 2.41 per cent of the world’s land area but supports about 17.5 per cent of the world’s population. India’s average population density as per Census 2011 is 382 persons per sq km.
Key idea 2 : Population of Brazil — Brazil is the most populous country in the South American continent. As per the textbook with about 19 crore people in Census 2010 it ranks 5th in the world, and also 5th in area. Brazil has 5.6 per cent of the world’s land and 2.78 per cent of the world’s population; so density is about 23 persons per sq km.
Key idea 3 : Comparison and a simple calculation — India’s density is 382 and Brazil’s about 23; so India has about 16 times more people per sq km than Brazil. The reason is that India has smaller area (about 32.8 lakh sq km) but more people, while Brazil has larger area (about 85 lakh sq km) but fewer people. For example in 1,000 sq km India has on average 3,82,000 and Brazil about 23,000 people.
- Easy : 10,000 people in 500 sq km. Density? — 10,000 ÷ 500 = 20.
- Medium : How many times is India’s density Brazil’s? — 382 ÷ 23 ≈ 16 times.
- Exam-type : What does high density mean? — More people in less space.
In the figure: Method of finding population density.
In Brazil’s 2022 census the population was found to be about 203 million, about 12.3 million more than 2010; annual growth 0.52 per cent, the lowest since 1872 (as per several sources; check with the book).
People divided by space.
More population does not always mean higher density; the area must also be seen.
Memory clue: Density = population ÷ area. Memory clue: "People divided by space".
Spot the difference
| Point | India | Brazil |
|---|---|---|
| Population (as per book) | About 121 crore (2011) | About 19 crore (2010) |
| Share of world land | 2.41 % | 5.6 % |
| Density | 382 per sq km | About 23 per sq km |
Practice questions
- 1What is population density?
- 2Write information about India’s population.
- 3Write information about Brazil’s population.
- 4Why is India’s density higher than Brazil’s?
- 5If population is 40,000 and area 200 sq km, what is the density?
- 6What is a census?
- 7Compare India’s and Brazil’s share of world land and population.
- 8Write advantages and disadvantages of high density.
Show answers (try them yourself first)
- 1Average people living per sq km.
- 2121 crore (2011); second in world; density 382.
- 3About 19 crore (2010); 5th; density about 23.
- 4Less area but more people.
- 540,000 ÷ 200 = 200.
- 6Counting of population done by government every 10 years.
- 7India: 2.41% land, 17.5% people; Brazil: 5.6% land, 2.78% people.
- 8Student writes own.
Distribution of Population
In a market the crowd gathers where there are shops, water and roads; nobody stays in a barren corner. In countries too people live more where facilities exist.
Distribution of population is the picture of where and in what proportion people live in a country. It is not the same everywhere (uneven).
Key idea 1 : Distribution in India — In India population is very unevenly spread. Because of fertile and flat land and availability of water, the northern plains have had settlements for many centuries. Because of farming, industry and trade the population is concentrated in a few places like Delhi, Kolkata, Mumbai, Pune, Bengaluru and Chennai. On the other hand in mountainous, desert and dense forest areas density is low because of difficult access, lack of facilities and a hard life.
Key idea 2 : Distribution in Brazil — In Brazil too distribution is uneven. Most Brazilians live within about 300 km of the Atlantic coast, especially in the south-east and eastern coastal plain; agriculture and industry have developed well there so density is high. The interior of the Amazon basin is very sparsely populated; unfavourable climate, heavy rain, inaccessibility and dense forest mean settlements occur only in a few places. The central and western parts are less populated, while the highlands have moderate density.
Key idea 3 : Factors affecting distribution — Geographical factors: relief (plain or mountain), climate (extreme or mild), soil (fertile or barren) and water. Economic and social factors: farming, industry, trade, transport and urban facilities. That is, people live more where life is easy and livelihood chances are higher.
- Easy : Why high density in the Ganga plains? — Flat, fertile, water.
- Medium : Where do most Brazilians live? — Near the Atlantic coast.
- Exam-type : Why is the Amazon basin sparse? — Forest, heavy rain, hard access.
In the figure: Factors affecting distribution of population.
People where there is convenience.
Population is not the same everywhere; plains and coast dense, mountains, desert and forest sparse.
Memory clue: Flat + fertile + water + industry = dense settlement. Memory clue: "Where convenience, there crowd".
Spot the difference
| Region | Density | Reason |
|---|---|---|
| Ganga plains, coast | High | Fertile, water, industry |
| Thar desert, Himalayas | Low | Dry/cold, hard access |
| Amazon interior | Low | Forest, heavy rain |
Practice questions
- 1Write factors affecting distribution of population in India.
- 2Why is population concentrated near the coast in Brazil?
- 3Why is settlement sparse in the Amazon basin?
- 4Why is density low in the Thar desert?
- 5Name four densely populated cities in India.
- 6Explain the relation between relief and population.
- 7Compare distribution in both countries.
- 8Write how to read a density map.
Show answers (try them yourself first)
- 1Relief, climate, soil, water, farming, industry, trade.
- 2Agriculture and industry developed, easier climate.
- 3Dense forest, heavy rain, hard access.
- 4Dry climate, lack of water.
- 5Delhi, Kolkata, Mumbai, Chennai.
- 6More in plains; less in mountains.
- 7Both uneven; India dense in plains, Brazil on the coast.
- 8Read density by the colour index.
Population Composition: Sex Ratio and Age
Looking at how many boys and girls of what age are in an admission list shows the picture of a class. A similar picture of a country is shown by the composition of its population.
Sex ratio is the number of females per 1,000 males. The age-sex pyramid is a graph that shows the proportion of males and females in different age groups.
Key idea 1 : Sex ratio — As per the graph in Brazil the number of women has always been more than men and has increased further since 2001. In India men outnumber women; there have been fluctuations in the ratio in recent decades and a slight improvement after 1991. The reasons for the low ratio in India are to be considered; ‘Beti Bachao, Beti Padhao’ is the need of the country.
Key idea 2 : Age-sex pyramid — The pyramid is used to study age and sex related aspects of a region’s population; it shows the proportion of children, youth and old. In both countries the number of young is high, but India has a higher proportion of children and Brazil has a higher proportion of people above 80 years than India. That is, Brazil’s population is slowly ageing.
Key idea 3 : Working and dependent age groups — People of working age (about 15 to 64) are considered the working population. Children and the old are dependent age groups. As India has a higher proportion of youth its working population is large; but it becomes a strength only if they are given education and employment. If the proportion of dependents increases, the burden on earners increases and the economy is strained.
- Easy : 940 females per 1,000 males means? — Sex ratio 940.
- Medium : What does a wide-base pyramid show? — High proportion of children.
- Exam-type : Dependent age groups? — Children and the old.
In the figure: Elements of population composition.
Per 1,000 males: how many females?
Sex ratio means females per 1,000 males — not the other way round.
Memory clue: Sex ratio = females per 1,000 males. Memory clue: "Thousand men, how many women?".
Spot the difference
| Point | India | Brazil |
|---|---|---|
| Sex ratio | More men, fewer women | More women |
| Proportion of children | Higher | Lower |
| Proportion of old | Lower | Higher |
Practice questions
- 1What is sex ratio?
- 2Compare the sex ratios of India and Brazil.
- 3Write the use of the age-sex pyramid.
- 4Write the reasons for low sex ratio in India.
- 5Why is Brazil’s population ageing?
- 6State the difference between working and dependent population.
- 7What will be the effect on the economy if dependent age groups increase?
- 8What will you do to improve the sex ratio?
Show answers (try them yourself first)
- 1Number of females per 1,000 males.
- 2India more men; Brazil more women.
- 3To study sex proportions by age groups.
- 4Discrimination against girls, biased thinking — student discusses and writes own.
- 5Birth rate is falling and life expectancy is rising.
- 6Ages 15–64 working; children and old dependent.
- 7Burden on earners increases; strain on economy.
- 8Education and equal chances for girls — student writes own.
Growth, Life Expectancy and Literacy
If marks were 90 last year and 85 this year, marks fell but you have not failed. Likewise a falling population growth rate does not mean the population is decreasing.
Growth rate is the percentage by which population grew in a decade. Life expectancy is the average number of years a person born in a country is expected to live. Literacy rate is the percentage of people who can read and write.
Key idea 1 : Population growth rate — In Brazil the growth rate has fallen considerably. In India the population increased by about 18.2 crore from 2001 to 2011. India’s growth rate was high until 1971, then stabilised and is now declining, but the population is still growing. A line going down on the graph means growth is less than the previous decade, not that the population is falling. As per the textbook Brazil’s population may not increase in the next two decades.
Key idea 2 : Life expectancy — Increase in life expectancy is a sign of a society’s development. When health facilities improve, progress is made in medicine and nutritious food is available, average life expectancy increases. As per the graph in the textbook Indians live about 68 years and Brazilians about 75 years on average. In 1960 India’s life expectancy was about 41 years and it will keep increasing.
Key idea 3 : Literacy and census — Literacy is an important measure of the quality of population and the graphs in the textbook show that Brazil’s literacy rate is higher than India’s. Census is the counting of population every ten years. In India it is done at the start of the decade (1961, 1971...) and in Brazil the IBGE institute does it at the end of the decade (1960, 1970...). The first census of both countries was in 1872.
- Easy : If the graph line goes down? — Growth is less, population still rising.
- Medium : Reasons for rising life expectancy? — Health facilities, nutritious food, medical progress.
- Exam-type : When is the census in India? — At the start of the decade.
In the figure: Census and important years.
India’s next census (Census 2027) in two phases: houselisting 1 April to 30 September 2026 and population enumeration in February 2027; reference date 1 March 2027; first fully digital census and with caste enumeration after 1931 (as per several sources; check with the book).
Lower growth ≠ lower population.
A fall in growth rate does not mean population fell; it only grows more slowly.
Memory clue: Lower growth, higher life expectancy, higher literacy = development. Memory clue: "Gro-Life-Lit".
Spot the difference
| Point | India | Brazil |
|---|---|---|
| Growth rate | Falling, still growing | Fallen a lot |
| Life expectancy (as per book) | About 68 years | About 75 years |
| Literacy | Lower | Higher |
Practice questions
- 1What is life expectancy?
- 2State the difference between falling growth rate and falling population.
- 3Write reasons for rising life expectancy.
- 4Compare literacy of India and Brazil.
- 5When is the census held in India and Brazil?
- 6Explain the relation between life expectancy and population growth.
- 7What should be done for proper use of manpower?
- 8Write two measures to control population growth.
Show answers (try them yourself first)
- 1Expected average years a newborn will live.
- 2Lower growth rate = grows slower; falling population = number decreases.
- 3Health facilities, medical progress, nutritious food.
- 4As per the book Brazil’s literacy is higher.
- 5India at the start of the decade; Brazil at the end.
- 6When life expectancy rises deaths fall and population can grow.
- 7Education, skills and employment.
- 8Education, awareness, health services — student writes own.