Population density

Also called: Arithmetic density, Crude density, Density of population · Topic: Population of India: Distribution, Density, Growth and Composition · NCERT: Class 12, Ch 2 "The World Population: Distribution, Density and Growth"; Class 12, Ch 1 "Population: Distribution, Density, Growth and Composition"

Meaning

Population density (also called arithmetic density or crude density) is the number of people living on each unit of land, usually per sq km. You find it by dividing the total population by the total area.

• It tells us how crowded a place is. It is the starting point for studying how people and land are linked.
• It is only a crude measure (a rough measure). It does not tell us how much food or work the land can give.

Explanation

How it is worked out

• Formula: Arithmetic density = total population ÷ total area (sq km).
• Why it is called "crude":
• It counts every sq km as the same.
• Fertile plain, desert, forest and snowy mountain all get equal weight.

• So two places can show the same figure but face very different pressure on their land.

• Where the numbers come from: the decennial Census (a count of people held once every 10 years).

• The first modern count was taken between 1865 and 1872. It was not held at the same time in every region [2].
• The first synchronous census (held at the same time across the whole country) was in 1881 [2].
• Census 2011 was the last census held. The 2021 census was postponed because of the COVID-19 pandemic, so 2011 figures are still the latest official density data [2].

What makes density high or low

• High density needs:
• flat land
• fertile soil, such as the alluvial soil (fine soil laid down by rivers) of the Ganga plain
• plenty of water
• a long history of settled farming

• jobs, trade and towns

• Low density comes from:

• steep slopes
• cold climate
• thick forests
• poor soil

• poor transport

• Result: across the world, river valleys and plains are crowded, while deserts and polar lands have few people.

India's density over time

• 1951: 117 persons per sq km.
• 2011: 382 persons per sq km.
• Change: a rise of more than 200 persons per sq km in 50 years.
• India's land area did not change.

• So the whole rise came from population growth.

• Range in Census 2011: from 17 in Arunachal Pradesh to 11,297 in NCT of Delhi. Delhi is about 660 times as dense as Arunachal Pradesh.

Two better measures that build on it

• India is an agricultural country, so NCERT adds two ratios that compare people with farmland:
• Physiological density = total population ÷ net cultivated area. Net cultivated area is land actually sown with crops in a year, counted only once.

• Agricultural density = agricultural population ÷ net cultivable area. The agricultural population is cultivators, agricultural labourers and their families.

• Both show the pressure on land that actually feeds people, which arithmetic density cannot show.

Where it occurs

India: spatial pattern (Census 2011)

Density level	States/UTs	Why
High: northern plains	Bihar 1,102 (final figure 1,106), West Bengal 1,029, Uttar Pradesh 828	Flat Ganga plain, fertile alluvial soil, plenty of water, old farming settlements
High: Peninsula	Kerala 859, Tamil Nadu 555	Coastal plains, heavy rain in Kerala, rice farming, fishing, trade, town growth
Moderate	Assam, Gujarat, Andhra Pradesh, Haryana, Jharkhand, Odisha	A mix of plains with plateaus, forests or dry land
Low	Himalayan states and north-eastern hill states (not Assam)	Steep slopes, cold, forests, poor soil and transport. Arunachal Pradesh is lowest at 17
Very high	Union Territories (not the Andaman and Nicobar Islands)	Small and mostly urban: Delhi 11,297, also Chandigarh and Puducherry. The Andaman and Nicobar Islands are forested islands with few people

• In one line: density is highest on the northern plains and the coastal plains. It is lowest in the Himalaya, the north-eastern hills and dry or forested interiors.

World

• Dense: river valleys and fertile plains.
• Sparse: hot deserts and cold polar lands.

Next data: Census 2027

• It will be the 16th census and the 8th since Independence. It will be India's first digital census [2][3].
• Data will be collected on mobile phones and checked almost live on the CMMS (Census Management & Monitoring System) portal. People can fill in their own details (self-enumeration), and each enumeration area will be geo-referenced (tied to its location on a map) [2].
• Phase I (Houselisting): April–September 2026. Phase II (Population Enumeration): February 2027 [2][3].
• Reference date: 00:00 hours, 1 March 2027. For Ladakh and the snow-bound areas of J&K, Himachal Pradesh and Uttarakhand, it is 1 October 2026 [2][3].

Don't confuse with

• Physiological density: it divides total population by net cultivated area, not total area. So it is always higher than arithmetic density.
• Agricultural density: its numerator is only the agricultural population (farmers, farm labourers and their families), and it divides by net cultivable area. Arithmetic density uses the total population and total area.
• Population distribution: this is where people live across space (the pattern). Density is a ratio, people per sq km.
• Most dense state vs most dense unit: Bihar is the most dense state. NCT of Delhi (a UT) is the most dense unit overall.

Prelims Hooks

• India's density: 117 (1951) → 382 (2011) persons per sq km.
• Lowest: Arunachal Pradesh (17). Highest overall: NCT of Delhi (11,297). Highest state: Bihar (1,102 provisional, 1,106 final).
• Order of high-density states (NCERT): Bihar (1,102) > West Bengal (1,029) > Kerala (859) > Uttar Pradesh (828) > Tamil Nadu (555).
• Trap: Assam is a moderate-density state, not a low-density north-eastern hill state.
• Trap: UTs have very high density, except the Andaman and Nicobar Islands.
• Census basics: Union List subject (entry 69, Seventh Schedule), run under the Census Act, 1948. First synchronous census in 1881. Census 2027 is the first digital census [2][3].

Mains Points

• Spatial pattern (GS-I): relief, climate, soil and water decide where people settle.
• The fertile, well-watered Ganga plain (Bihar, West Bengal, UP) and the coastal plains (Kerala, Tamil Nadu) are crowded.
• The Himalayan and north-eastern hill states are thinly peopled.

• In UTs like Delhi, towns and jobs, not farming, cause very high density.

• Limits of arithmetic density: it is a crude ratio because it ignores land quality.

• In a farming country, physiological and agricultural density show the real pressure on cropland.
• High agricultural density in Bihar and Kerala leads to small holdings, land fragmentation (farms split into tiny scattered plots) and disguised unemployment (extra workers on a farm who add nothing to output).

• People then move out, for example from Bihar and UP to Punjab, Delhi and Maharashtra. Policy answers include land consolidation, non-farm rural jobs, agro-processing and skilling.

• Data gap: with Census 2021 postponed, planners still use 2011 density data. The digital, geo-referenced Census 2027 will give new and more detailed density data for planning [2][3].

Related concepts

• Physiological density
• Agricultural density

Read more

• Density of population: arithmetic, physiological and agricultural