Theory of Demographic Transition

3. Theory of Demographic Transition

The Theory of Demographic Transition explains how a country's birth rate, death rate, and

population growth rate change together as it moves from a traditional, largely agrarian economy

toward a modern, industrialised one. It describes this movement in four stages:

Stage 1 — High Stationary Stage. Both the birth rate (number of live births per 1,000

population per year) and the death rate (number of deaths per 1,000 population per year)

are HIGH, and roughly balance each other out — so total population growth stays LOW and

roughly stationary. This is characteristic of pre-modern, traditional agrarian societies with

little access to modern medicine, poor sanitation, and frequent famine/epidemic, where high

birth rates are needed simply to offset high mortality (especially infant mortality).

Stage 2 — Early Expanding Stage. The death rate starts falling rapidly — thanks to

improved medicine, sanitation, and food security — while the birth rate remains high

(social attitudes, family size norms, and reproductive behaviour change far more slowly than

medical/public-health conditions do). Because births now far outnumber deaths, population

growth accelerates sharply. This is the stage of the fastest population growth in a

country's demographic history.

Stage 3 — Late Expanding Stage. The birth rate now also starts falling — as

industrialisation, urbanisation, rising female education and workforce participation, and

wider availability of family planning reduce the economic and social incentive for large

families — while the death rate continues to fall slowly and stays low. Population growth

continues but at a decelerating pace, since the gap between birth and death rates is

narrowing.

Stage 4 — Low Stationary Stage. Both birth and death rates settle at LOW levels, again

roughly balancing each other, so population growth becomes low and stable once more — but this

time at a much larger total population size than Stage 1 began with. This is the pattern

characteristic of developed, industrialised economies today.

Where does India stand? India entered Stage 2 after independence (1951 onward), as public

health measures, vaccination programmes, and improved food availability (following the Green

Revolution) sharply cut the death rate while the birth rate stayed high — producing the rapid

population growth discussed in Section 2. Since the 1980s, India's birth rate has also been

falling — more sharply in some states than others — moving the country from Stage 2 toward

Stage 3. In fact, recent National Family Health Survey (NFHS-5, 2019–21) data show India's

national Total Fertility Rate (the average number of children a woman is expected to have

over her lifetime) has fallen to around the replacement level of about 2.1, though this

national average masks considerable variation — some southern and western states are already

well into Stage 3/4, while a few northern states have a higher fertility rate and remain closer

to Stage 2. …