Demography is the study of human populations — their size, growth, distribution and structure. For NDA Geography, the Census of India 2011 is a goldmine of facts: total population, density, sex ratio, literacy and growth rate. These numbers come up almost every year, so let us learn them clearly and remember them for good.
What Demography and Census Mean
Demography comes from two Greek words — demos (people) and graphy (description). So demography literally means the scientific description of people. It studies how many people live in an area, how fast their numbers change, and how they are spread out.
A census is the official, complete head-count of every person in a country. In India, a census is conducted once every ten years (a decadal census). The first complete census was held in 1872 under Lord Mayo, and the first synchronous census in 1881 under Lord Ripon. Since 1881, the census has been carried out without a break.
Census 2011 was the 15th census since 1872 and the 7th after Independence. Its theme was “Our Census, Our Future”.
The census is conducted by the Office of the Registrar General and Census Commissioner of India, which works under the Ministry of Home Affairs. The power to conduct it comes from the Census Act, 1948, and the subject “census” is listed in the Union List of the Constitution.
Why does a census matter so much? It is the single biggest source of demographic data for the whole country. The government uses census figures to plan schools, hospitals, roads and welfare schemes, to draw electoral boundaries, and to share resources between states. For a geographer or an NDA aspirant, the census is the master sheet of facts about India’s people. Understanding it well means you can answer a whole cluster of questions on population, society and the economy.
The Big Census 2011 Numbers
If you remember nothing else, remember these headline figures. They are the most directly asked facts in NDA Geography, and a single page of revision here can fetch you two or three marks.
- Total population: 121.08 crore (1.21 billion) — about 17.5% of the world’s people on just 2.4% of the world’s land.
- Males: 62.31 crore; Females: 58.74 crore.
- Population density: 382 persons per sq km.
- Sex ratio: 943 females per 1000 males.
- Literacy rate: 74.04%.
- Decadal growth (2001–2011): 17.7%.
India was the second most populous country in 2011 (after China). Uttar Pradesh is the most populous state, and Sikkim the least populous state.
A handy memory trick: India added about 18.1 crore people between 2001 and 2011 — a number larger than the entire population of Brazil at that time. To put the scale in perspective, just five states — Uttar Pradesh, Maharashtra, Bihar, West Bengal and Andhra Pradesh — together account for nearly half of India’s entire population. Uttar Pradesh alone, with about 19.98 crore people, would rank among the most populous countries in the world if it were a separate nation.
Notice also that the population is unevenly distributed. A huge share of Indians live in the fertile river plains and along the coasts, while vast stretches of desert, mountain and forest remain thinly settled. This uneven spread is the reason a single “national average” can be misleading, and why examiners often test the state-wise extremes.
Population Density Explained
Population density tells us how crowded a place is. It is simply the number of people living per unit area.
Population density = Total population ÷ Total area (measured in persons per square kilometre).
India’s density rose from 325 in 2001 to 382 persons per sq km in 2011. But this average hides huge differences:
- Most dense state: Bihar (1106 persons/sq km).
- Least dense state: Arunachal Pradesh (17 persons/sq km).
- Most dense UT: Delhi (11,320 persons/sq km).
- Least dense UT: Andaman & Nicobar Islands.
Do not confuse density rankings with total population rankings. Bihar has the highest density, but Uttar Pradesh has the highest total population.
Sex Ratio and Why It Matters
Sex ratio measures the balance between men and women in a population. In India, it is expressed as the number of females per 1000 males. (Note: many western countries express it the opposite way, as males per 1000 females.)
Sex ratio = (Number of females ÷ Number of males) × 1000. India’s 2011 figure was 943, up from 933 in 2001.
There is also the child sex ratio (0–6 years), which fell to a worrying 919 in 2011 — the lowest since Independence. This decline points to issues like female foeticide and son-preference.
- Highest sex ratio (state): Kerala (1084 females per 1000 males).
- Lowest sex ratio (state): Haryana (879).
- Highest among UTs: Puducherry; Lowest among UTs: Daman & Diu.
Kerala has the best overall sex ratio, but the highest child sex ratio belongs to a different region. Read the question carefully — “sex ratio” and “child sex ratio” are different statistics.
Literacy Rate Across India
In the census, a person aged 7 years and above who can read and write with understanding in any language is counted as literate. The literacy rate is the percentage of literate people in the population aged 7 and above.
National literacy (2011): 74.04%. Male literacy = 82.14%; Female literacy = 65.46%. The gender gap is closing but still wide.
- Most literate state: Kerala (94%).
- Least literate state: Bihar (61.8%).
- Most literate UT: Lakshadweep.
- Least literate UT: Dadra & Nagar Haveli.
Encouragingly, female literacy rose faster than male literacy between 2001 and 2011, helping to narrow the long-standing gender gap in education.
Population Growth and the Demographic Transition
The natural growth of a population depends on the difference between births and deaths.
Natural Growth Rate = Birth Rate − Death Rate. When migration is added, we get the actual growth of population.
The Demographic Transition Theory explains how a country’s population changes as it develops, in three broad stages:
- First stage: high birth rate, high death rate → population grows slowly. (Pre-industrial, rural societies.)
- Second stage: birth rate stays high but death rate falls due to better food and medicine → population explodes. (India was here for much of the 20th century.)
- Third stage: both birth and death rates fall → population stabilises. (Developed countries.)
India is currently moving from the second towards the third stage. Its decadal growth slowed from 21.5% (1991–2001) to 17.7% (2001–2011), the sharpest decline in independent India — a sign that family-planning and rising education are working.
Two more terms are worth knowing here. The birth rate is the number of live births per 1000 people in a year, and the death rate is the number of deaths per 1000 people in a year. India’s death rate has fallen steeply because of better healthcare, vaccination and food security, while its birth rate is now falling more gradually as families choose to have fewer children. The gap between these two rates is exactly what fuels the population growth recorded in each census.
The year 1921 is called the “Great Divide” or demographic divide. Before 1921 growth was uneven; after 1921 India’s population grew continuously.
What Decides Where People Live
People are not spread evenly across India. The Northern Plains are densely packed, while deserts and mountains are sparsely settled. Several factors decide this distribution.
Physical factors
- Relief: flat, fertile plains attract people; steep hills and mountains repel them.
- Climate: moderate climate with reliable rainfall supports dense settlement.
- Soil and water: rich alluvial soil and rivers draw large populations (e.g. the Ganga plain).
Human factors
- Industries and cities offer jobs and attract migrants.
- Transport and connectivity make an area easier to live and trade in.
- Agricultural prosperity like that of Punjab supports dense rural populations.
The most thinly populated regions of India are the Himalayas, the Thar Desert, the Rann of Kutch, and dense forest belts of the northeast and central India.
Rural-Urban Split and Age Structure
In 2011, India was still mostly rural: about 68.8% of people lived in villages and 31.2% in towns and cities. Importantly, between 2001 and 2011 the urban population grew faster than rural for the first time — India is steadily urbanising.
The age structure of a population is the share of people in different age groups. It is shown using a population pyramid:
- A wide base means many children — a young, growing population (like India).
- A narrow base with a wide top means an ageing population (like Japan).
India is a young country — a large share of its people are of working age. This is called the “demographic dividend”, a potential boost to the economy if these people get jobs and skills.
Worked Example: Calculating Sex Ratio
Let us practise the sex-ratio formula with a simple example.
A district has 4,80,000 males and 4,56,000 females. Find its sex ratio (females per 1000 males).
So this district has a sex ratio of 950, which is higher than India’s national average of 943 — meaning it is relatively more balanced.
Always check the direction of the ratio. In India it is females per 1000 males. If a question gives males per 1000 females, the larger and smaller numbers swap places.
High-Yield Records to Memorise
NDA examiners love “highest and lowest” questions. Here is a quick reference table of Census 2011 record-holders.
Among States
- Most populous: Uttar Pradesh — Least populous: Sikkim.
- Highest density: Bihar — Lowest density: Arunachal Pradesh.
- Highest sex ratio: Kerala — Lowest: Haryana.
- Highest literacy: Kerala — Lowest: Bihar.
- Highest decadal growth: Meghalaya — Lowest (negative): Nagaland.
Among Union Territories
- Most populous UT: Delhi — Least populous: Lakshadweep.
- Highest density: Delhi — Lowest: Andaman & Nicobar Islands.
Nagaland was the only state to record a negative growth rate in the 2001–2011 decade — a favourite trick question.
Common Mistakes Students Make
Demography questions are easy marks, but careless errors cost candidates. Watch out for these traps.
Mixing up density (people per sq km) with total population. Bihar leads in density; Uttar Pradesh leads in total population. They are not the same state.
- Confusing sex ratio (943) with child sex ratio (919).
- Forgetting that literacy is counted only for people aged 7 years and above, not the whole population.
- Assuming India is the most populous country — in 2011 it was the second, after China.
- Thinking the first census was 1881 — the first census was 1872; the first synchronous one was 1881.
Previous-Year Question and Quick Recap
Q. According to the Census of India 2011, which one of the following states has the highest population density?
Answer: Bihar, with about 1106 persons per square kilometre, has the highest population density among Indian states. (West Bengal and Uttar Pradesh follow.) Do not confuse this with the National Capital Territory of Delhi, which has the highest density among Union Territories at over 11,000 persons per sq km.
- Census 2011 = 15th census, population 121.08 crore, second most populous country.
- Density 382 persons/sq km; highest Bihar, lowest Arunachal Pradesh.
- Sex ratio 943 (child sex ratio 919); best Kerala, worst Haryana.
- Literacy 74.04%; best Kerala, worst Bihar.
- Decadal growth 17.7%; demographic transition explains the slowdown.
- 1921 = the Great Divide year; India enjoys a young-age demographic dividend.
Frequently asked questions
What was India's total population in Census 2011?
India's population in 2011 was 121.08 crore (about 1.21 billion), making it the second most populous country in the world after China at that time.
What is the difference between sex ratio and child sex ratio?
Sex ratio is the number of females per 1000 males in the whole population (943 in 2011). Child sex ratio counts only children aged 0 to 6 years (919 in 2011), and it is monitored separately because it reflects recent gender bias at birth.
Which state had the highest literacy rate in Census 2011?
Kerala had the highest literacy rate at about 94%, while Bihar had the lowest at around 61.8%. The national average literacy rate was 74.04%.
What is the demographic dividend?
The demographic dividend is the economic benefit a country can gain when a large share of its population is of working age. India, being a young country, can boost its economy if these people are given jobs, education and skills.
How often is the Census of India conducted and by whom?
The Census of India is conducted once every ten years (decadal) by the Office of the Registrar General and Census Commissioner of India, under the Ministry of Home Affairs. The 2011 census was the 15th since 1872.
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