The procedure of amending the Constitution in a federal system is normally rigid.Indian Constitution provides that some amendments require a special majority.Supremacy of judiciary is another very important feature of a federal state where there is an independent judiciary to interpret the Constitution and to maintain its sanctity.The Supreme Court of India has the original jurisdiction to settle disputes between the Union and the States.A unitary system is governed constitutionally as one single unit, with one constitutionally created legislature. A unitary state is a sovereign state governed as one single unit in which the central government is supreme and any administrative divisions (sub national units) exercise only powers that the central government chooses to delegate.This is one of the federal features of the Indian constitution.After this procedure the amendment is signed by the head of the state i.e; the President.
And both the union government and the central government derive their powers from the constitution.: The constitution of India is a rigid constitution and this is one of the basic features of federal constitution.
The federation is a union because it is indestructible and helps to maintain the unity of the country.