The Census of India: 1881 to the 2027 round

Detail

1. What a census is

• Census: a complete count of every person in a country at one fixed moment. Nobody is sampled. Every household is visited or counted.
• Census vs sample survey:
• A census method covers every unit in the population.
• A sample survey (like NSS or PLFS) covers only a small, carefully chosen part. It then uses that part to estimate the whole.

• A census is costly and slow. So it runs only once in ten years. Sample surveys fill the gaps in between.

• Synchronous census: the whole country is counted with reference to the same date and hour. This stops people being counted twice, or missed, when they move.

2. History: 1872 to 2011

• 1872: the first count, under Lord Mayo. It was non-synchronous, meaning different regions were counted at different times.
• 1881: the first synchronous census, led by Census Commissioner W.C. Plowden.

• It has been decennial (held every ten years) ever since.

• 1951: the first census after Independence.

• 2011: the 15th census overall and the 7th after Independence.
• 2021: the round was postponed because of COVID. It became Census 2027.
• Census 2027 will be the 16th census and the 8th since Independence [4].
• The run from 1881 to 2011 was never broken. 2021 is the first round that missed its ten-year slot.

3. Legal and institutional base

• Census Act 1948: the law that governs the census.
• It makes answering compulsory.

• It keeps each person's answers confidential. Only totals are published.

• Entry 69, Union List (Seventh Schedule): the census is a Union subject. Only Parliament can make laws on it.

• Office of the Registrar General & Census Commissioner, India (ORGI):
• It sits under the Ministry of Home Affairs (MHA) and was set up in 1949.

• Exam trap: NCERT lists "Census of India" and "RGI" as if they were two bodies. They are one office. The same officer is both Registrar General and Census Commissioner.

• Other data systems run by the RGI:

• SRS (Sample Registration System): a large, continuous sample survey. It gives yearly estimates of IMR (infant deaths per 1,000 live births), TFR (average number of children a woman would have in her lifetime) and MMR (maternal deaths per 1 lakh live births). These are needed between two censuses.
• CRS (Civil Registration System): the ongoing, compulsory registration of births and deaths under the Registration of Births and Deaths (RBD) Act 1969.

• NPR (National Population Register): a register of the usual residents of India.

• RBD (Amendment) Act 2023: this changed the CRS in several ways.

• The Registrar General must keep a national database of registered births and deaths. State Chief Registrars and local Registrars must share their data with it [9].
• The birth certificate becomes a single document to prove date and place of birth, for example for school admission. This applies to people born after the Act came into force [9].
• The database may be shared with bodies that keep the population register, electoral rolls and ration cards [9].
• Certificates can now be issued electronically [9].
• Parents' Aadhaar numbers must be given when a birth is registered [9].

4. What the census collects

• Phase I: Houselisting and Housing Census: data on each building and house, housing condition and amenities (drinking water, toilet, electricity, cooking fuel, assets).
• Phase II: Population Enumeration: data on each person.
• Size and density:
  • Density means persons per km².
  • Formula: Density = Population ÷ Area (km²).
• Sex ratio:
  • In India it means females per 1,000 males.
  • Formula: Sex ratio = (Females ÷ Males) × 1,000.
• Literacy:
  • A person aged 7 or above who can read and write, with understanding, in any language counts as literate.
  • Formula: Literacy rate = Literates ÷ Population aged 7+ × 100.
• Migration: the place of birth and the last place of residence.
• Rural-urban split.
• Birth and death rates, and life expectancy, including fertility questions.

• Workers:

  • Main worker: worked 6 months (183 days) or more in the year before the census.
  • Marginal worker: worked for less than 6 months.

• Economic use: the census is the sampling frame (the master list of households and villages) from which NSS and PLFS draw their samples. If the census is old, every survey built on it is weaker.

5. Census 2011: key numbers

Indicator	Census 2011	Comparison
Population	121.09 crore (final figure)	102.87 crore in 2001 (NCERT)
Sex ratio	943	Rural 949, urban 929 [7]
Literacy	74.04%	64.83% in 2001, a rise of 9.21 percentage points [6][7]
Density	382 persons/km² [8]	—
Decadal growth	17.7% (17.64%)	Males 17.19%, females 18.12% [8]

• The first provisional release in 2011 put the population at "1,210 million" [6].
• Females were about 48.5% of the population in 2011 [7].
• 17.64% was the lowest decadal growth since Independence.
• Female literacy rose from 53.7% to 65.5% between 2001 and 2011. It still lagged male literacy.

Worked example: decadal growth rate

• Formula: Decadal growth (%) = (P₂₀₁₁ − P₂₀₀₁) ÷ P₂₀₀₁ × 100
• Using the figures: (121.09 − 102.87) ÷ 102.87 × 100 = 18.22 ÷ 102.87 × 100 ≈ 17.7%

Worked example: sex ratio

• In 2011 there were about 58.75 crore females and 62.33 crore males.
• Sex ratio = 58.75 ÷ 62.33 × 1,000 ≈ 943

Worked example: density (toy numbers)

• Suppose a district has 20 lakh people living on 5,000 km².
• Density = 20,00,000 ÷ 5,000 = 400/km²

6. Census 2027: timeline and mechanics

• Postponement and notification:
• The 2021 round was delayed by COVID.

• Census 2027 was notified in June 2025. It will be done in two phases, along with caste enumeration [3].

• Cabinet approval: the scheme was approved at a cost of ₹11,718.24 crore [2].

• Manpower: about 30 lakh field functionaries (enumerators, supervisors, master trainers, charge officers, and principal and district census officers) [2].
• Reference date (the instant to which every count refers):
• 00:00 hrs, 1 March 2027 for most of India [2].

• 00:00 hrs, 1 October 2026 for Ladakh and the snow-bound, non-synchronous areas of J&K, Himachal Pradesh and Uttarakhand [2].

• Phase I: Houselisting and Housing Census (HLO), April–September 2026:

• Each State or UT picks its own 30-day window inside this period [4].
• That window is preceded by an optional 15-day self-enumeration period [4].

• HLO has been launched state by state. The first round included Andhra Pradesh, Arunachal Pradesh, Haryana, Chandigarh, Madhya Pradesh and Chhattisgarh [5].

• Phase II: Population Enumeration (PE), February 2027:

• It covers demographic, socio-economic, cultural, migration and fertility details of each person [4].

• In the snow-bound areas, PE is held in September 2026 instead [2].

• Firsts:

• First digital census:
  • Data are collected on mobile apps.
  • A secure Self-Enumeration Portal lets households enter their own details online before the enumerator visits [4].
• First caste enumeration since 1931:
  • Until 2011, the census counted only Scheduled Castes and Scheduled Tribes [4].
  • The Cabinet Committee on Political Affairs (CCPA) decided on 30 April 2025 to count all castes, in Phase II [4].

• SECC 2011 (Socio-Economic and Caste Census) was a separate exercise, not part of the census. Its caste data remain unreleased.

• Verify current: how far fieldwork has progressed (the HLO window ends in September 2026) and any revised budget or schedule.

7. Why Census 2027 matters: the stakes

• Delimitation (redrawing constituency boundaries and deciding each state's number of seats):
• Articles 82 and 170 freeze the allocation of seats until the first census after 2026. Census 2027 is that census.

• Chain of effect:

  • The new census counts population.
  • Seats may shift between states.
  • States with slower population growth (mostly southern states) fear they will lose relative weight.

• Women's reservation:

• The 106th Amendment (2023) inserted Art 334A, which reserves one-third of seats in the Lok Sabha and state Assemblies for women.

• It takes effect only after the census that follows the Act, and the delimitation based on it.

• Welfare coverage:

• NFSA (National Food Security Act) coverage is 75% of the rural and 50% of the urban population, calculated on 2011 figures.

• Population has grown since 2011. So people who should be eligible may be left out.

• Statistical frames: NSS, PLFS and other survey frames, and per-capita figures, still rest on 2011 data. This may bias the estimates.

8. Reading the population series (crore)

1901	1951	1961	1971	1981	1991	2001	2011
23.83	35.7	43.8	54.6	68.4	81.8	102.7	121.0

• This is NCERT's table.
• Note: the 2001 figure is 102.87 crore and the 2011 final figure is 121.09 crore. NCERT's table rounds or truncates these numbers.
• The population rose by over 97 crore in 110 years (1901–2011).
• Average annual growth rate (the yearly compound rate that would produce the decade's increase):
• 2.2% in 1971–81 → 1.97% in 1991–2001 → 1.64% in 2001–11.

• Growth is slowing, which is a sign of demographic transition (the move from high birth and death rates to low ones).

• 1921, the "Year of Great Divide":

• Before 1921, population rose and fell with famines and epidemics.
• After 1921, it rose steadily every decade.

• Cross-ref: colonial-economy-1947.

• India became the world's most populous country in 2023 (UN estimate).

Prelims Hooks

• 1872 census (Lord Mayo) = non-synchronous. 1881 (W.C. Plowden) = first synchronous census.
• Census = Entry 69, Union List. Law = Census Act 1948. Office = ORGI, under MHA (1949).
• Census 2027 = 16th census, 8th after Independence. Census 2011 = 15th and 7th [4].
• Reference date = 1 March 2027, 00:00 hrs. Snow-bound areas = 1 October 2026 [2].
• Cost ₹11,718.24 crore, about 30 lakh field functionaries [2].
• Caste enumeration approved by the CCPA on 30 April 2025. It is the first since 1931. Until 2011 only SC/ST were counted [4].
• Census 2011: sex ratio 943 (rural 949, urban 929), literacy 74.04%, density 382/km², decadal growth 17.64% [7][8].
• The SRS (not the census) gives yearly IMR, TFR and MMR. The CRS runs under the RBD Act 1969 (amended 2023). All three (census, SRS, CRS) are run by the same RGI.
• The RBD Amendment Act 2023 created a national database of births and deaths kept by the Registrar General, and made the birth certificate a single proof of date and place of birth [9].
• Trap: SECC 2011 is not a census under the Census Act 1948. Its caste data are unreleased.

Mains Points

• Data gap and policy quality:
• A 16-year gap between censuses (2011 to 2027) weakens survey frames, per-capita estimates and welfare targeting such as NFSA coverage.

• A timely census is basic public infrastructure for evidence-based policy (GS-III, Indian economy and planning).

• Caste enumeration: benefits and risks:

• Benefit: it gives an evidence base for reservation, sub-categorisation and targeting welfare.

• Risks: caste lists are hard to classify (thousands of self-reported names), the data can be politicised, and the process needs openness (compare SECC 2011, whose caste data were never released).

• Delimitation and federalism:

• Seats reallocated on Census 2027 figures could penalise states that controlled population growth.

• The same census also triggers women's reservation (Art 334A), so the two reforms are linked (GS-II).

• Digital census: gains and concerns:

• Gains: apps and self-enumeration mean faster results, fewer errors and real-time monitoring.
• Concerns: the digital divide, data privacy and linking data with the NPR and the RBD database. Confidentiality under the Census Act 1948 must be protected.