What is Demography?
The study of human population — its size, structure, and composition — and how these change over time. Studies: age groups, gender, education, occupation, religion, and movements of people within/across countries.
- Governments use it to plan: schools, hospitals, roads, housing, water, energy
- If many young children → more schools needed
- If many elderly → more healthcare facilities needed
- If more working-age population → more jobs needed
- Businesses assess customers based on age, gender, income
Key Demographic Concepts
Number of live births per 1,000 people per year. High birth rate = growing young population.
Number of deaths per 1,000 people per year. Falling death rate = people living longer.
Birth Rate MINUS Death Rate. Positive = growing population. Negative = shrinking.
Movement of people between places. Immigration (into a country) vs Emigration (out of a country). Affects population size & composition.
Average number of years a person is expected to live. India's life expectancy has increased significantly since independence.
Average number of children per woman. Replacement level = 2.1. India's fertility rate has been declining steadily.
World Population Trends
📊 World population growth — from 2.5 billion (1950) to 8.2 billion (2025); expected to peak at 10.3 billion mid-2080s
📅 2025: 8.2 billion people
📅 2050: Expected 9.7 billion
📅 Mid-2080s: Peak ~10.3 billion, then gradual decline
⚠️ Some countries (China, Japan, Italy) already have shrinking populations!
✅ India's population still growing (for now); many African nations growing rapidly
- Antibiotics, vaccines & oral rehydration solution — revolutionary medicines
- Better water & sanitation → fewer child deaths
- Reduction in malaria & diarrhoea deaths
- Economic prosperity reaching more people
- Result: People living much longer → population exploded!
India's Population
- 2023: India surpassed China as world's most populous country!
- Indians = ~17% of world population
- India's population grew from 361 million (1951) to 1.46 billion (2025)
- Population growth rate has been declining — good sign!
- UP, Maharashtra, Bihar, West Bengal — most populous states
📊 India's population growth trajectory — steady rise from 361 million (1951) to 1,460 million (2025)
Birth Rate, Death Rate & Migration
- Total Fertility Rate fallen from ~6 (1950s) to ~2 now
- Better education + women's empowerment
- Urbanisation → smaller families preferred
- Family planning programmes
- Some southern states already below replacement level!
- Internal migration: Rural → Urban (for jobs)
- Inter-state migration: UP/Bihar → Delhi/Mumbai/Bangalore
- International: India's diaspora = largest in world (~18 million!)
- Indian diaspora sends home billions in remittances
Age & Gender Structure
India has a young population — ~65% under 35 years! This is the demographic dividend: when working-age population is large relative to dependents → huge economic potential. But only if we provide education, skills, and jobs!
| India — Young Population 🌱 | Japan/Germany — Ageing Population 👴 |
|---|---|
| Large working-age population | Shrinking working-age population |
| More workers per retiree | Fewer workers per retiree |
| Need: education & jobs for youth | Need: pensions & elder care |
| Potential for rapid economic growth | Slower economic growth challenge |
Quick Summary
- Demography = study of population size, structure, composition and change over time
- World: 2.5B (1950) → 8.2B (2025) → peak ~10.3B in mid-2080s, then decline
- India 2023: Surpassed China = world's most populous! (~1.46 billion, 17% of world)
- Demographic Dividend = large young working-age population = economic opportunity IF we invest in education & jobs
- India's birth rate & fertility rate declining — family sizes shrinking
- Birth rate - Death rate = Natural growth rate
- Census every 10 years — data for all government planning