Explanation:

After every census, a readjustment is to be made in (a) allocation of seats in the Lok Sabha to the states, and (b) division of each state into territorial constituencies. Parliament is empowered to determine the authority and the manner in which it is to be made. Accordingly, the Parliament has enacted the Delimitation Commission Acts in 1952, 1962, 1972 and 2002 for this purpose.

The 84th Amendment Act of 2001 also empowered the government to undertake readjustment and rationalisation of territorial constituencies in the states on the basis of the population figures of 1991 census. Later, the 87th Amendment Act of 2003 provided for the delimitation of constituencies on the basis of 2001 census and not 1991 census. However, this can be done without altering the number of seats allotted to each state in the Lok Sabha. The reason for restricting constituencies on past population is that legislators should not promote population growth in their own constituencies for future electoral gains.