India became the world’s most populous country in 2023, yet its fertility has already fallen below replacement level. That paradox — a huge population with slowing growth — is the core of this chapter.

What UPSC asks. Mains GS I asks about the demographic dividend, ageing, the population-control debate, migration and the sex ratio. Prelims asks demographic terms (TFR, replacement level, dependency ratio), Census and NFHS figures, and policy milestones such as the National Population Policy, 2000. The same material serves Geography (population geography) and Economy (employment).

Key sub-topics

Sub-topic	What to know
Demographic profile	Census 2011 totals, density, growth; NFHS-5 fertility
Demographic transition	Four stages; where India stands
Demographic dividend	Working-age bulge; the window and its conditions
Ageing	Rising elderly share; care and pension needs
Migration	Census 2011 migration; seasonal and distress migration
Population policy	1952 programme, NPP 2000, the freeze on seat allocation

Read the topic page, then use the revision sheet and practice set.