Delimitation Commission of India
Delimitation commission or Boundary commission of India is a Commission established by the Government of India under the provisions of the Delimitation Commission Act. The main task of the commission is redraw the boundaries of the various assembly and Lok Sabha constituencies based on a recent census. The representation from each state is not changed during this exercise. However, the number of SC and ST seats in a state are changed in accordance with the census.
The Commission is a powerful body whose orders cannot be challenged in a court of law. The orders are laid before the Lok Sabha and the respective State Legislative Assemblies. However, modifications are not permitted.
Delimitation commissions have been set up four times in the past - In 1952, 1963, 1973 and 2002 under Delimitation Commission acts of 1952, 1962, 1972 and 2002.
The government had suspended delimitation in 1976 until after the 2001 census so that states' family planning programs would not affect their political representation in the Lok Sabha. This had led to wide discrepancies in the size of constituencies, with the largest having over three million electors, and the smallest less than 50,000. 
Commission of 2002
The recent delimitation commission was set up on 12 July 2002 after the 2001 census with Justice Kuldip Singh, a retired Judge of the Supreme Court as its Chairperson. The Commission has submitted its recommendations. On December 2007, the Supreme Court on a petition issued notice to the central government asking reasons for non implementation. On 4 January 2008, the Cabinet Committee on Political Affairs (CCPA) decided to implement the order from the Delimitation Commission. The recommendations of the Delimitation Commission was approved by the President, Pratibha Patil on 19 February 2008. This means that all future elections in India for states covered by the commission will be held under the newly formed constituencies.
The present delimitation of parliamentary constituencies has been done on the basis of 2001 census figures under the provisions of Delimitation Act, 2002. However, the Constitution of India was specifically amended in 2002 not to have delimitation of constituencies till the first census after 2026. Thus, the present Constituencies carved out on the basis of 2001 census shall continue to be in operation till the first census after 2026.