The essentials
India's population is very unevenly spread. Uttar Pradesh has the largest population among the states, while states like Sikkim and Mizoram have small populations. High density is found in the fertile northern plains, deltas and coastal plains, while the Himalayas, the Thar desert and forested hill areas are thinly populated. Physical factors (relief, climate, water), socio-economic factors (agriculture, industry, transport, urbanisation) and historical factors explain this pattern.
Density in India was 382 persons per km² at the 2011 Census. Bihar had the highest density among states and Arunachal Pradesh the lowest. Physiological density (total population ÷ net cultivated area) and agricultural density (agricultural population ÷ net cultivable area) give a clearer picture of pressure on farmland.
Key points
- Phase I (1901–1921): stagnant or stationary phase; growth was very low, even negative in 1911–1921, because of high birth and death rates due to famines, epidemics and poor health services.
- Phase II (1921–1951): steady growth; death rates fell with better health and sanitation. 1921 is called the year of the great demographic divide.
- Phase III (1951–1981): population explosion; death rates fell rapidly while birth rates remained high due to development activities and better living conditions.
- Phase IV (after 1981): growth remained high but started slowing down, mainly due to falling birth rates linked with later marriage and better female education.
- Growth rate over a decade = (later population − earlier population) ÷ earlier population × 100.
- Growth can be positive or negative; natural growth is births minus deaths, and induced growth includes migration.
Exam tips
Remember the phases with their labels and causes. For calculations, always divide the change by the earlier year's population.
Common mistakes
Do not call 1951 the year of demographic divide; it is 1921, after which population has grown continuously.