Population growth

Also called: Population change, Growth rate of population · Topic: Population of India: Distribution, Density, Growth and Composition · NCERT: Class 12, Ch 2 "The World Population: Distribution, Density and Growth"; Class 12, Ch 1 "Population: Distribution, Density, Growth and Composition"

Meaning

Population growth is the change in the number of people living in an area between two points in time, usually given as a percentage. An example is the change in India's population between Census 2001 and Census 2011. Growth has two parts: natural growth (births minus deaths) and induced growth (people moving in minus people moving out).

It matters because the speed of growth decides how much pressure falls on food, jobs, housing and schools. India's growth has passed through four phases since 1901. Each phase is a step in the demographic transition (the shift from high births and high deaths to low births and low deaths).

Explanation

Parts of growth: natural and induced

Part	What it is	How it is measured
Natural growth	Births minus deaths	Crude birth rate (CBR) minus crude death rate (CDR)
Induced growth	People moving in minus people moving out	In-migration minus out-migration

• Crude birth rate (CBR): live births in a year for every 1,000 people.
• Crude death rate (CDR): deaths in a year for every 1,000 people.
• The NCERT chapter covers only natural growth.
• Positive growth: births are more than deaths, or more people arrive than leave.
• Negative growth: the population falls. Since 1901, India has seen this only once, in 1911-21.

Measuring growth: three tools

• Decadal growth rate: the percentage change over ten years, from one Census to the next.
• g = (P2 − P1) ÷ P1 × 100. P1 is the population at the earlier Census. P2 is the population at the later Census.
• Worked example: P1 = 1,028.7 million (2001), P2 = 1,210.8 million (2011).

• g = 182.1 ÷ 1,028.7 × 100 ≈ 17.64%.

• Annual (exponential) growth rate: the average growth per year within a decade. It was 1.64% a year for 2001-11.

• Doubling time: how many years a population takes to double if it keeps growing at its current yearly rate.
• Shortcut (Rule of 70): doubling time ≈ 70 ÷ annual growth rate in %.
• At about 2.2% a year (1961-81): about 32 years.
• At 1.64% a year (2001-11): about 43 years.
• At about 0.9% a year (UN estimate, mid-2020s): about 78 years.

The four phases of India's growth (cause → process → result)

Census year	Population (million)	Decadal growth (%)	Phase
1901	238.4	—	I
1911	252.1	5.75	I
1921	251.3	−0.31	I
1931	279.0	11.00	II
1941	318.6	14.22	II
1951	361.0	13.31	II
1961	439.2	21.64	III
1971	548.1	24.80 (peak)	III
1981	683.3	24.66	III
1991	846.4	23.87	IV
2001	1,028.7	21.54	IV
2011	1,210.8	17.64	IV

• Phase I, 1901-21: stagnant (stationary) phase. The population hardly grew.
• Both births and deaths were high, so they almost cancelled out.
• Births were high because of early marriage, illiteracy, and children being seen as extra hands on the farm.
• Deaths were high because of poor health and medical services, illiteracy among most people, and poor distribution of food and other basic needs.

• In 1911-21 the population actually fell, because of famines, plague epidemics and the 1918 influenza pandemic ("Spanish flu"). Deaths were higher than births.

• Phase II, 1921-51: steady growth phase.

• Cause: better health, sanitation, transport and communication.
• Process: food reached famine areas faster and diseases were better controlled, so the death rate fell. The birth rate stayed high.
• Result: steady growth of 11.00%, 14.22% and 13.31% per decade. This is mortality-induced growth (growth caused by fewer deaths, not more births).

• The growth came despite the Great Depression, World War II (1939-45) and the 1943 Bengal famine.

• Phase III, 1951-81: population explosion phase.

• Cause: planned development through the Five-Year Plans, better medicine, vaccination, malaria control and better living conditions.
• Process: the death rate fell sharply, but births stayed high. Early marriage was still common, and the family planning programme (1952) had little effect at first. The gap between births and deaths became very large.

• Result: the population almost doubled in 30 years (361.0 m → 683.3 m), at about 2.2% a year. Migrants added to this growth (induced growth).

• Phase IV, after 1981: phase of declining growth.

• Cause: a higher mean age at marriage (people marry later, so they have fewer years to bear children), a better quality of life and, above all, female education.
• Process: the birth rate fell, so growth slowed in every decade: 23.87% → 21.54% → 17.64%.
• Result: growth is still positive. About 182 million people were added in 2001-11. The base is very large, and many young people are now entering child-bearing age. This is called population momentum.

Census: where the data comes from

• First modern Census: 1865-1872. It was not held at the same time in all regions [2].
• First synchronous Census (the whole country counted at one fixed time): 1881 [2].
• The 2021 round was delayed by COVID-19, so Census 2011 is still the latest completed count [2]. As a result, there is no official decadal growth figure for 2011-21.

Where it occurs

• India, by region:
• The southern and western states, such as Kerala and Tamil Nadu, are further along the demographic transition, and their growth is slow.

• The north-central states, such as Bihar and Uttar Pradesh, are still growing fast.

• India, by stage: India today is in the late stage of the transition. Births are falling, deaths are low, and the population is youthful but ageing.

• Induced growth in India (1951-81): Tibetans (after 1959), Bangladeshis (around 1971), Nepalis and people from Pakistan moved into India.
• World:
• Western Europe and Japan have finished the transition (low births, low deaths, near-zero growth).

• Much of sub-Saharan Africa is still in Stage 2 (high births, falling deaths, rising growth).

• How growth is measured in India: through the Census. It is a Union subject, entry 69 of the Union List, Seventh Schedule, and is run under the Census Act, 1948 and the Census Rules, 1990 [3].

• Census 2027 is the 16th Census and the 8th since Independence [2][3].
• Its reference date is 00:00 hours on 1 March 2027. For Ladakh and the snow-bound areas of Jammu & Kashmir, Himachal Pradesh and Uttarakhand, it is 1 October 2026 [2][3].
• It is India's first digital Census (data collected on mobile phones) [2]. It is also the first Census since Independence to count all castes [2][3].

Don't confuse with

• Decadal growth rate vs annual growth rate: the decadal rate is the change over ten years (17.64% for 2001-11). The annual rate is the average per year in that decade (1.64%). Do not use one in place of the other.
• Natural growth vs induced growth: natural growth is births minus deaths (CBR − CDR). Induced growth is in-migration minus out-migration. The NCERT chapter deals only with natural growth.
• Declining growth (Phase IV) vs negative growth: in Phase IV the rate slows, but the population still grows. Negative growth means the population actually falls, and in India this happened only in 1911-21 (−0.31%).
• Falling growth rate vs falling absolute increase: the rate fell to 17.64% in 2001-11, yet about 182 million people were still added. This is because of the large base and population momentum.

Prelims Hooks

• Only decade of decline: 1911-21 (−0.31%). That is why 1921 is called the "Great Divide" of India's demographic history.
• Highest decadal growth: 1961-71 (24.80%), followed by 1971-81 (24.66%). Trap: the peak is not 1951-61 (21.64%).
• Phase order: Stagnant (1901-21) → Steady growth (1921-51) → Population explosion (1951-81) → Declining growth (after 1981).
• Phase–cause pairs: Phase II growth came from falling deaths (mortality-induced). The Phase IV slowdown came from falling births (female education, later marriage).
• Census 2011: 1,210.8 million; decadal growth 17.64%; annual growth 1.64%; doubling time ≈ 70 ÷ 1.64 ≈ 43 years. Trap: NCERT calls growth "steadily increasing". This is false, because the rate has fallen since 1971-81.
• First Census: 1872 (not synchronous). First synchronous Census: 1881 [2]. Census 2027: 16th Census, reference date 1 March 2027, and the first digital Census [2][3].

Mains Points

• Deaths fell before births did. Better health, sanitation and transport cut deaths from 1921 onwards, but birth rates stayed high until the 1980s.
• This gap caused the 1951-81 explosion, when the population nearly doubled in 30 years.

• It explains India's young age structure and the heavy pressure on land, jobs, housing and cities (GS-I).

• Female education is the strongest brake on growth.

• It raises the age at marriage, lowers the number of children families want and improves the use of health services.

• The fall in decadal growth from 24.66% (1971-81) to 17.64% (2001-11) shows its effect. This supports investing in girls' schooling rather than forced population control.

• Regional gaps and the data gap.

• States such as Kerala and Tamil Nadu are near the end of the transition, while Bihar and Uttar Pradesh are still growing fast. This affects seat delimitation, the sharing of Finance Commission funds and migration from the north to the south.
• No Census was held in 2021, so the 2011 figures are 15 years old. Census 2027 will give the first decadal growth figure since 2011 [2].

Related concepts

• Decadal growth rate
• Stagnant phase of population growth
• Steady growth phase
• Population explosion phase
• Phase of declining growth

Read more

• Growth of population: the four phases since 1901