BharatNotes Census 2021 was postponed (the first Census skipped in India since 1872) and the actual enumeration began in April 2026 as part of the 2027 Census, which will include caste for the first time in nearly a century. For Prelims, continue using Census 2011 data as the baseline (treat it as the latest official) but explicitly flag the postponement, the 2027 timeline, the digital-app first-time methodology, the caste inclusion controversy, and the link to delimitation (post-2028). UPSC has asked at least one Census-policy question in recent years and 2026-27 papers will almost certainly probe the new methodology.
The Census problem is one of the most consequential data gaps in UPSC Prelims preparation, and aspirants must handle it with two simultaneous frames: the static demographic data they will be tested on, and the policy story of why the data is now 15 years old. Let me lay out the verified facts and then the preparation implication.
The 2021 Census was originally scheduled to begin its House Listing phase on 1 April 2020, with Population Enumeration in February 2021. COVID-19 halted operations in March 2020, and the Census remained postponed year after year — making it the first Census skipped in India since the decadal exercise began under the British in 1872. The Registrar General of India's term was extended multiple times. In October 2024, the Government of India confirmed that the Census would begin in 2025, with completion by 2026 and delimitation of Lok Sabha seats to follow by 2028. As of May 2026, the Census is officially the '2027 Census of India' — the House Listing and Housing Census phase began on 1 April 2026 and will run until September 2026, and the Population Enumeration phase is scheduled for February 2027. Two methodological firsts: the data will be collected electronically via a mobile app (Census of India app), and caste will be enumerated for the first time since 1931 (the 1941 Census collected caste but its release was disrupted by WWII; post-Independence, only SC/ST counts have been published).
For Prelims preparation, this creates four practical implications. First, all baseline demographic figures must be quoted from Census 2011: India's population at 121 crore (1.21 billion), sex ratio 943, child sex ratio 919, literacy rate 74.04 percent, urban population share 31.16 percent, density 382 per sq km, decadal growth 17.7 percent (2001-2011). Use these numbers in every static answer because they are the latest official figures UPSC will treat as canonical. Do not use intermediate Sample Registration System (SRS) or National Family Health Survey (NFHS) estimates as substitutes for Census numbers — these have different sampling frames and UPSC distinguishes between them.
Second, learn the Census-policy story as a current affairs topic in its own right. UPSC has asked Prelims and Mains questions on Census methodology, the Registrar General of India's constitutional position (under Article 246 read with the Census Act 1948), the distinction between Census (enumeration, mandatory) and NPR (National Population Register, registration-based), and the controversies around caste enumeration. The 2026-27 Prelims will almost certainly probe at least one of these. Memorise: the Census is conducted under the Census Act 1948 (a Union subject under Entry 69 of the Union List), the responsible authority is the Office of the Registrar General and Census Commissioner (under the Ministry of Home Affairs), and the data is the constitutional basis for Lok Sabha seat allocation under Article 81 and delimitation under Article 82.
Third, anticipate caste-Census-specific questions. The decision to include caste in the 2027 Census is the most politically consequential change since 1931 and connects to multiple syllabus areas: reservation policy and the Mandal Commission, Article 340 (commission for backward classes), the Indra Sawhney judgment (1992) and the 50 percent ceiling, the Socio Economic and Caste Census 2011 (SECC, which was not a Census proper and whose caste data was never released), and the 2022-23 Bihar caste survey precedent. Build a one-page note linking all these threads.
Fourth, track the delimitation linkage. Article 82 mandates readjustment of Lok Sabha seats after every Census, but the 84th Constitutional Amendment (2001) and 87th (2003) froze the inter-state seat allocation at 1971 Census levels until the first Census after 2026. With the 2027 Census now imminent, post-2028 delimitation will almost certainly be a hot Prelims and Mains topic — covering the federal tension (southern states with successful demographic transition will receive proportionally fewer seats than northern states with higher growth), the role of the Delimitation Commission, and the 2008 delimitation precedent.
The topper consensus on Census-pending topics — Shakti Dubey emphasised in her topper's talk that she maintained a separate file for 'evolving demographic policy' precisely because the Census delay made static demographic data unreliable for any post-2020 framing. Ishita Kishore (AIR 1, CSE 2022) similarly noted that current-affairs-integrated demographic answers scored better than rote Census-2011 recall. The lesson: treat Census 2011 as your baseline number-source, but treat 'the Census story' itself as a high-priority current affairs topic with five-year shelf life.
One final tactical note: when UPSC sets questions touching demographics in Prelims 2026 and 2027, expect at least one question to probe the 2027 Census methodology directly (electronic enumeration, caste inclusion, two-phase design, delimitation linkage). Prepare a 200-word mental note on the Census's constitutional, legal, and procedural framework — that compact note will pay disproportionate dividends.
