Readjustment of State Assembly Constituencies

Readjustment, or delimitation, means revising the allocation of seats and the territorial boundaries of parliamentary or State Assembly constituencies after a census. In this context, parliamentary constituencies are Lok Sabha constituencies. The Constitution establishes population-based representation, while Parliament determines the authority and procedure for readjustment.

Population-based representation

The Constitution seeks broadly equal population per seat for both Lok Sabha and State Assembly constituencies.

• Under Article 81, Lok Sabha seats should be allocated among States so that the population-to-seat ratio is, as far as practicable, the same for all States; this principle does not apply to a State whose population does not exceed six million.
• Under Article 81(2), the population-to-seat ratio of each parliamentary constituency should, as far as practicable, be the same throughout the State.
• Under Article 170(2), the ratio between the population of each Assembly constituency and the seats allotted to it must, so far as practicable, be the same across the State.
• Population means the population recorded by the last preceding census whose relevant figures have been published. The phrase “so far as practicable” permits limited departures from strict mathematical equality.

Readjustment after a census

A census does not itself alter seats or boundaries. Readjustment must occur through the constitutionally prescribed parliamentary framework.

• Under Article 82, after each census the allocation of Lok Sabha seats among States and the division of each State into parliamentary constituencies must be readjusted by the authority and in the manner determined by Parliament.
• Under Article 170(3), Assembly constituencies must similarly be readjusted after each census by the authority and in the manner determined by Parliament.
• Parliament exercises its election-related legislative power under Article 327, including through delimitation legislation establishing the Delimitation Commission.
• Under the Delimitation Act, 2002, boundaries may also account for physical features, administrative boundaries, communication facilities and public convenience.

Present census baselines

The Constitution presently separates the census basis for determining total seats from that used for territorial boundaries.

• Until figures of the first census taken after 2026 are published, allocation of Lok Sabha seats among States and the total number of Assembly seats need not be readjusted from the allocation based on the 1971 Census.
• Parliamentary and Assembly territorial constituencies may be readjusted using the 2001 Census population figures during this period.
• The 84th Constitutional Amendment Act, 2001 continued the freeze, while the 87th Constitutional Amendment Act, 2003 provided the 2001 Census baseline for territorial readjustment.
• The freeze does not automatically end in 2026. The constitutional trigger is publication of relevant figures from the first census conducted after that year.

Commencement and legal protection

Completed delimitation does not immediately alter representation in an existing legislature.

• The President specifies the date from which readjustment takes effect; until then, elections may be held from the existing constituencies.
• Parliamentary readjustment does not affect representation in the existing Lok Sabha until its dissolution. Article 170(3) provides the corresponding rule for an existing State Assembly.
• Under Article 329(a), the validity of laws relating to delimitation or allotment of seats made under Articles 327 or 328 cannot be questioned in any court.