ExplainerDelimitation
Delimitation explained, and why the 131st Amendment failed
How Lok Sabha seats are shared among states, why the numbers have been frozen since 1976, and what the government's April 2026 attempt to change them would have done.
The short answer
Delimitation redraws constituencies and fixes how many seats each state gets, based on population. State seat totals have been frozen on the 1971 census until the first census after 2026. The Constitution (131st Amendment) Bill, which would have lifted the Lok Sabha cap to 850 and allowed delimitation on the 2011 census, won 298 votes to 230 on 17 April 2026, short of the two-thirds needed.
What is delimitation?
Delimitation is the process of fixing how many seats each state gets in the Lok Sabha and its assembly, and of drawing the boundaries of each constituency. The Constitution’s principle, as PRS Legislative Research summarises it, is that seats should be shared in line with population so that constituencies across states hold roughly equal numbers of people. Articles 81 and 82 require seats to be readjusted after each census, and Article 170 applies a similar rule to state assemblies. The work is done by a Delimitation Commission. The last one was constituted in 2002 and its orders were finalised in 2008.
Why have state seat totals not changed in 50 years?
Because the Constitution froze them on the 1971 census, and the freeze was extended in 2001. The 42nd Amendment of 1976 fixed each state’s share of seats on 1971 figures until the first census after 2000. The 84th Amendment of 2001 extended this “until the publication of the first census after 2026”. PRS notes the stated aim was to support population stabilisation, so that states which slowed population growth would not lose seats. Constituency boundaries inside states were redrawn in the 2000s, but each state’s total stayed the same.
What did the 131st Amendment Bill propose?
It would have raised the Lok Sabha’s maximum size from 550 to 850 and let Parliament decide by law when to hold delimitation and which census to use. Up to 815 seats would have gone to states and up to 35 to Union Territories, according to PRS. PRS notes that Parliament could have made these decisions by a simple majority. A companion Delimitation Bill would have set up a commission chaired by a serving or former Supreme Court judge, with the Chief Election Commissioner or a nominee and the state election commissioner, to redraw seats on the 2011 census, LiveLaw reported. All three bills, including a Union Territories Laws (Amendment) Bill, were introduced on 16 April 2026.
How was it linked to women’s reservation?
The bill would have let one-third reservation for women take effect right after a fresh delimitation. The Constitution (106th Amendment) Act, 2023 reserves one-third of seats in the Lok Sabha and assemblies for women, but only after delimitation based on the first census taken after the Act. The Centre notified the 2023 Act on 16 April 2026, LiveLaw reported, but under the Act the reservation itself still waits on delimitation. PRS notes that the current census has a reference date of 1 March 2027 and that delimitation on it is unlikely to be finished before the 2029 Lok Sabha election.
Why did it fail?
It did not get the two-thirds of members present and voting that a constitutional amendment needs. On 17 April 2026 the Lok Sabha voted 298 for and 230 against. With 528 members voting, 352 votes were needed. South First reported it was “the first Bill to be defeated in the Lok Sabha during the 12 years of the Narendra Modi government”. Union minister Kiren Rijiju then withdrew the Delimitation Bill and the Union Territories bill.
Opposition parties argued that redrawing seats on the 2011 census would cut the share of southern and north-eastern states, and questioned the timing while a new census was under way, LiveLaw reported. Most parties said they supported women’s reservation itself.
Which states would have gained or lost?
On PRS’s illustration, with the House kept at its current size, Uttar Pradesh and Bihar would have gained seats and Tamil Nadu and Kerala would have lost them.
PRS also flagged that a larger Lok Sabha would change its ratio to the Rajya Sabha from about 2.2:1 to 3.3:1, which matters in joint sittings and in presidential elections, and would raise the cap on the size of the Union Council of Ministers.
What happens now?
As of October 2026 the freeze stands: the next readjustment is tied to the first census published after 2026, which is the census now under way. The Tribune reported on 1 September that the government was considering a special session from 18 to 20 September for a reworked bill, possibly with safeguards for states’ seat shares. No such session was reported to have been held, and no revised bill had been reported as of 11 October. The Monsoon Session was adjourned sine die on 13 August but, unusually, had not been prorogued, Business Standard reported, which leaves the government free to recall Parliament.
Delimitation milestones
- 197642nd Amendment freezes state seat totals on the 1971 census until after 2000.
- 200184th Amendment extends the freeze until the first census after 2026.
- 2002-2008Last Delimitation Commission redraws boundaries within states.
- 2023106th Amendment reserves one-third of seats for women, after the next delimitation.
- 16 Apr 2026131st Amendment, Delimitation and UT bills introduced.
- 17 Apr 2026Lok Sabha vote: 298 for, 230 against; amendment fails, companion bills withdrawn.
- 1 Mar 2027Reference date for most of Census 2027.
The documents
- The Constitution (131st Amendment) Bill, 2026PRS Legislative Research, 17 April 2026
- The Delimitation Bill, 2026PRS Legislative Research, 11 October 2026