"The Indian constitution is both flexible and rigid" explain
Indian Constitution is both flexible and rigid in nature. Our Constitution makers cautiously opted for this approach for the following reasons:
It is flexible so that the constitution can respond to the changes of the society and incorporate new legislation's from time to time easily.
It is rigid so that the constitution is not easily arm twisted by political parties for their narrow political gains.
Therefore, there are certain provisions in the constitution which can be changed by simple majority of the parliament.
Constitutional Amendment Bill on the other hand requires special majority by both the houses of the parliament present and voting.
Any changes in the power structure between the Center and the State requires special majority of the parliament and ratification by half of the the state legislature.