The 84th amendment to the Constitution binds the next delimitation exercise with the new Census. It is this link that has upset southern states. The amendment, made in 2002, froze the number of Parliament seats to the 1973 delimitation exercise, which was based on the Census of 1971. It says that the next delimitation exercise would be undertaken after 2026, based on the first Census after that year.
Southern states controlled their population much better than their northern counterparts, and as such, they fear loss of political representation if the new re-mapping of the Lok Sabha seats is linked