Definitions [1]
Density of Population: The density of population is the number of persons living per unit of an area. It is usually expressed as number of people per square kilometre (sq km).
Formulae [4]
`"Density of population" = "Number of people in a defined area unit"/"Total area in square km of that particular area"`
Formula: Arithmetical Density
\[\text{Arithmetical density}=\frac{\text{Total Population}}{\mathrm{Total~Area}}\]
Formula: Physiological Density
\[\text{Physiological density}=\frac{\text{Total population}}{\text{Net cultivated area}.}\]
Formula: Agricultural Density
\[\text{Agricultural density}=\frac{\text{Total agricultural population}}{\text{Net cultivable area}}\]
Key Points
Key Points: Distribution of Population in India
- Dense population → Northern plains (Ganga–Brahmaputra region).
- Highest density (2011) → Bihar; also high in West Bengal & Kerala.
- Sparse population → Himalayan region, Thar Desert, North-East hills.
- Kerala → Most densely populated state in South India.
- Population density = Number of persons per sq. km.
Key Points: India's Population Compared With Other Major Countries
- India’s Population Share – India has only 2.4% of the world’s land but supports about 17.5% of the world’s population.
- Most Populous Country – India became the most populous country in the world in 2023, surpassing China.
- Population in 2024 – India’s total population was about 143.8 crore in 2024.
- Comparison with Other Countries – The USA, the third most populous, has 4.5% of the world’s population; Canada and Australia have less than 1% each.
- Census in India – Population data are collected every 10 years; the first full census was in 1881; the 2011 census was the 15th overall and 7th after Independence.
Key Points: Population: Distribution, Density and Growth
- Uneven Distribution – India’s population (1210 million in 2011) is unevenly distributed; Uttar Pradesh has the highest population.
- Large vs Small States – Big area does not mean big population (e.g., Rajasthan large area but less population; UP small area but very high population).
- Population Density (2011) – 382 persons per sq. km.; density has increased continuously since 1921.
- High Density Areas – Bihar (1102), West Bengal, Uttar Pradesh, Kerala and Delhi have very high population density.
- Low Density Areas – Arunachal Pradesh, Sikkim, Jammu & Kashmir and other hilly states have low density due to difficult terrain.
- Causes of Variation – Relief, climate, soil, water supply, urbanisation, industrialisation and migration affect population density.
- Types of Density –
i. Arithmetical: Total population ÷ total area
ii. Physiological: Total population ÷ cultivated land
iii. Agricultural: Agricultural population ÷ cultivable land
Key Points: Population Growth Since 1901
- Four Phases of Population Growth –
1901–1921: Stagnant growth (1921 called demographic divide)
1921–1951: Steady growth
1951–1981: Rapid high growth
1981–2011: High growth but slowing down - Demographic Divide (1921) – Population declined slightly due to epidemics, famines and World War I deaths.
- Rapid Growth (1951–1981) – Population almost doubled due to fall in death rate and improvement in health and living conditions.
- Slowing Growth After 1981 – Birth rate declined; growth rate reduced to 1.76% in 2011, showing success of family planning.
- Regional Variations – States like Bihar and Meghalaya have high growth; Kerala has very low growth; some small UTs show very high growth.
- Impact on Development – Fast population growth increases poverty, unemployment, housing shortage, illiteracy and pressure on basic facilities.
- Environmental & Ecological Impact – Overuse of land, forests and minerals causes pollution, soil degradation, loss of biodiversity and ecological imbalance.
Key Points: Index of Concentration
- Index of Concentration – It shows the percentage share of a state’s population in India’s total population (e.g., U.P. had about 19.5% in 2011).
- Uneven Distribution – Population is highly concentrated in plains, urban and industrial areas, while mountains, deserts and forests have low population.
- Physical Factors – Terrain, climate (rainfall & temperature), soil and water availability strongly affect population density.
- Economic Factors – Minerals, industries and transport facilities attract people and increase population density.
- Urbanisation – Urban centres have very high population density due to employment and better facilities.
- Types of Growth –
i. Natural growth = Birth rate – Death rate
ii. Migratory growth = Change due to migration
iii. Positive/Negative growth depends on increase or decrease in population. - Population Trend in India – India has mostly shown positive growth since 1872; 1921 was the only year of negative growth.
