Chapter 6 — Dynamics of Population

Chapter 6 of the Class 8 Social Science NCERT textbook (Exploring Society: India and Beyond), "Dynamics of Population", explores demography — the study of population size, structure, and change — covering birth rates, fertility rates, death rates, migration, demographic transition stages, India's population composition, sex ratio, the population pyramid, and the concept of demographic dividend.

• Demography and Its Uses — Demography studies human population composition — age, gender, occupation, religion — and how it changes over time. Governments use this data to plan schools, hospitals, roads, and water services, while businesses use it to understand customers.
• Key Population Indicators — Four key indicators determine a country's population: birth rate (live births per 1,000 people per year), fertility rate (average children per woman — 2.1 is replacement level), death/mortality rate (deaths per 1,000 people), and migration (movement of people within or across countries).
• Demographic Transition — Countries move through three stages: Stage 1 (high birth + death rates, slow growth), Stage 2 (death rates fall, birth rates stay high — rapid growth), and Stage 3 (both rates low, birth rates decline — slow or shrinking population). India was in Stage 1 until 1921, Stage 2 after 1951, and entered Stage 3 from the mid-1980s.
• Population Pyramid — A population pyramid graphs a country's population by age groups and gender. A wide base means a young, growing population (like India or Nigeria); a wide top indicates an ageing population (like Japan). India's pyramid is changing from a narrow triangle to a bell-shape as birth rates fall and the working-age middle widens.
• India's Demographic Dividend — India's large working-age population (nearly 65% aged 15–59, median age 28) represents a demographic dividend — economic growth potential from a young, productive workforce. This window is limited: growth in the young population is expected to decline after 2050.

1. 01In 2023, India surpassed China to become the world's most populous country, with Indians making up around 17% of world population.
2. 02World population grew from 2.5 billion (1950) to 8.2 billion (2025) and is projected to peak at 10.3 billion in the mid-2080s.
3. 03A fertility rate of 2.1 is the replacement level — above 2.1 the population grows; below 2.1 it may shrink.
4. 04India's fertility rate declined from 5.7 in 1950 to 1.9 in 2025, driven partly by the 'Hum do humare do' campaign (1952) and rising women's education.
5. 05China's One-Child Policy (1979–2015) dropped fertility from 7.5 to 1; China's population peaked at 1.43 billion in 2022 and is projected to fall to 1.31 billion by 2050.
6. 06India's child mortality fell from 271 per 1,000 live births (1950) to 28 in 2023; life expectancy rose from 30 years at independence to 70 years in 2024.
7. 07India's sex ratio improved from 933 (Census 2001) to 943 females per 1,000 males (Census 2011).
8. 08India's demographic dividend window will close post-2050 — the number of children under 15 peaked in 2011 and is now declining.
9. 09States like Kerala and Tamil Nadu already show significant population ageing compared to Bihar and Uttar Pradesh.
10. 10Uttar Pradesh holds the largest share (16%) of India's population among all states.
11. 11India's median age is 28, compared to Japan (50), Italy (48), Germany (47), China (40), and the USA (39).
12. 12Rapid urbanisation and higher female education are two key drivers behind declining birth rates globally.
13. 13Japan has raised the retirement age and deployed robotics and AI to manage labour shortages from its ageing population.