Population — The Increasing Numbers and Rising Problems

Q: A state has 9,00,00,000 people and an area of 1,50,000 km2. Find its population density.

Density = dfrac9,00,00,0001,50,000 = 600 persons per km2.

ICSE Class 10 · Biology · Chapter 15

What this chapter covers

Population and the population explosion in India
Main reasons for the sharp rise in population
Demography and population density
Birth rate, death rate and growth rate
Problems of population explosion: economic and social
Problems of population explosion: resources and environment
The need for population control
Surgical methods of population control

Key definitions

Population is the total number of individuals of a species living in a particular area at a particular time.

Population explosion is a very rapid and sudden increase in the size of a human population over a short period, when the number of births far exceeds the number of deaths.

Demography is the scientific study of human populations, including their size, density, distribution, composition by age and sex, and the changes caused by births, deaths and migration.

Population density is the number of individuals living in a unit area of land, usually expressed as the number of persons per square kilometre.

Birth rate is the number of live births per 1,000 individuals of a population in one year.

Death rate is the number of deaths per 1,000 individuals of a population in one year.

Growth rate of population is the change in the size of a population over one year, expressed as a percentage of the population or as a number per 1,000 people.

Unemployment is the condition in which people who are able and willing to work cannot find paid work.

Per capita income is the average income per person in a region or country, found by dividing the total income of the region by its population.

Price rise is a continuing increase in the general prices of goods and services, so that the same amount of money buys less than before.

Natural resources are materials and features of nature, such as land, water, forests, soil, minerals and fossil fuels, that people use to meet their needs.

Population control is the set of measures taken to slow down the growth of a population, mainly by reducing the birth rate, so that the population stays in balance with the resources available.

Key points

Population is the total number of individuals of a species in an area at a given time; India became the most populous country in 2023.
Population explosion is a rapid, sudden rise in population when births far exceed deaths.
The main cause of the explosion: the death rate fell sharply (epidemic control, vaccination, medicines, more food, safe water) while the birth rate stayed high (illiteracy, early marriage, son preference, children as economic support, social beliefs).
Demography is the scientific study of human populations and how they change.
Population density = total population ÷ land area, in persons per km²; India's density in 2011 was 382 per km².
Birth rate and death rate are the numbers of live births and deaths per 1,000 people per year.
Natural growth rate = birth rate − death rate; divide a rate per 1,000 by 10 to get a percentage.
Increase in population = (births + immigrants) − (deaths + emigrants).
Problems of population explosion: unemployment, over-exploitation of natural resources, low per capita income, price rise, pollution and unequal distribution of wealth.
Population control aims mainly to reduce the birth rate, through education, later marriage, awareness, health care and family planning.
Tubectomy: each fallopian tube is cut and tied in a female; ovulation, menstruation and hormones continue.
Vasectomy: each vas deferens is cut and tied in a male; semen is formed without sperms, testosterone continues, and it becomes effective only after about three months.
Both surgical methods are permanent, simple and safe, but do not protect against sexually transmitted diseases.

Questions answered

Define population explosion. Why is the word "explosion" used?

Population explosion is a very rapid and sudden increase in the size of a human population over a short period, when births far exceed deaths. The word is used because the growth speeds up and the population curve rises steeply like the letter J.

Give the main reason for the sharp rise in India's population after 1951.

The death rate fell sharply because of the control of epidemics, vaccination, better medicines, more food and safer drinking water, while the birth rate stayed high for a long time. The widening gap between births and deaths produced rapid growth.

List any four reasons why the birth rate in India remained high.

Illiteracy and lack of awareness of family planning; early marriage; preference for a male child; children seen as helpers in work and as support in old age. Fear of losing children and social or religious beliefs are also accepted.

Explain the terms (a) demography and (b) population density.

(a) Demography is the scientific study of human populations, including their size, density, distribution, composition and the changes caused by births, deaths and migration. (b) Population density is the number of persons living per unit area of land, usually per square kilometre.

A state has 9,00,00,000 people and an area of 1,50,000 km². Find its population density.

Density = dfrac9,00,00,0001,50,000 = 600 persons per km².

Define birth rate and death rate.

Birth rate is the number of live births per 1,000 individuals of a population in one year. Death rate is the number of deaths per 1,000 individuals of a population in one year.

A town of 4,00,000 people records 9,200 births and 2,800 deaths in a year. Find its birth rate, death rate and natural growth rate as a percentage.

Birth rate = dfrac9,2004,00,000 × 1000 = 23 per 1,000. Death rate = dfrac2,8004,00,000 × 1000 = 7 per 1,000. Natural growth rate = 23 - 7 = 16 per 1,000 = 1.6 per cent.

India's birth rate has been falling for many years. Why is India's population still increasing?

The birth rate is still higher than the death rate, so the growth rate is positive, only smaller than before. Because the base population is very large, even a small percentage growth adds more than a crore people each year.

Past board exam questions

ICSE 2027 sample paper · 2 marks

Kiran lived with his family in the outskirts of a city which had a lot of greenery around. After a few years, a number of factories mushroomed which affected the quality of life of the people living there. The picture shows a crowded industrial area: many factory buildings standing close together, with tall chimneys releasing smoke, storage tanks and trucks in front of them. Mention two reasons for population explosion in India.

Show answer

Any two: high birth rate with a falling death rate (better medical facilities); lack of awareness of family planning methods; illiteracy; early marriage; desire for a male child.

ICSE 2026 board paper · 1 mark

A health organisation wants to educate the rural audience about population control using visually engaging methods. Which of these would be effective? P. Posters Q. Loudspeakers R. Film shows S. Street plays

P, R and S
Q, R and S
P, Q and R
P, Q and S

Show answer

P, R and S

ICSE 2026 sample paper · 1 mark

Cultural revolution favours a steep rise in human population. Identify the correct sequence of revolution:

Tool making, Scientific and Industrial, Agricultural
Agricultural, Tool making, Scientific and Industrial
Scientific and Industrial, Agricultural, Tool making
Tool making, Agricultural, Scientific and Industrial

Show answer

Tool making, Agricultural, Scientific and Industrial

ICSE 2026 board paper · 1 mark

Explain the term 'Population Density' with reference to human beings.

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Population density is the number of persons living per unit area (e.g. per square kilometre) of a region at a given time.

ICSE 2026 sample paper · 1 mark

Explain the term Natality.

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Natality (birth rate) is the number of live births per 1000 individuals of a population per year.

ICSE 2025 board paper · 1 mark

The number of live births per thousand people per year is called:

Mortality
Population density
Population growth rate
Natality

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Natality

ICSE 2025 sample paper · 2 marks

Mention the surgical methods of contraception in: (a) Men (b) Women

Show answer

(a) Men – Vasectomy (vas deferens cut and tied). (b) Women – Tubectomy (fallopian tubes cut and tied).

ICSE 2025 board paper · 2 marks

In the last century, the human population has increased tremendously. Death rate has reduced and life expectancy has increased. This rapid growth has placed significant pressure on resources. Global cooperation is needed for environmental preservation. (a) Mention any one reason for reduction in the death rate. (b) Name any one resource that is under pressure due to population explosion.

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(a) Better medical facilities – vaccination and control of epidemic diseases (also better nutrition and sanitation). (Any one) (b) Fresh water (also land, food, forests, fossil fuels). (Any one)