There are 3 different types of constitutions, the unitary form, the federal form, and the confederation.
The example of a unitary form of constitution is U.K.. There is a single government and the states are not vested with powers . This is a centralized form of constitution and talks about concentration of powers at the higher level
In a federal form, the powers are divided btw the Centre and the state and they work complementary to each other. This form works on the principle of decentralization and there are usually 2 or more levels of government. Example the USA.
Confederation is an alliance or a group formed for some common place successful for some period of time but sometimes they work against the charter ex, European union.
Features of a federal constitution:
Two levels of government- there should be 2 levels of govt i.e., govt for whole nation and the regional level.
In India we have 2 levels of the government . In India the state government cannot be done away with except under article 352 or 356 during emergency that too only for a short duration of time.
Article 1 of the Indian constitution states that India should be a union of states . Article one cannot be done away with as it forms the basic feature of the constitution as enlisted by the constituent assembly.
Distribution of powers : there should be distribution of powers among the Centre and state and also the legislature, executive and the judiciary.
Article 246 (1) confers on parliament an ‘exclusive power’ to make laws with respect to any of the matters in list I.
Article 246 (3) confers an exclusive power on the states to make laws with respect to the matters enumerated in list II.
In addition to the two above-mentioned lists, the indian constitution includes a third list that lays down a wide and III .
(union list, state list and the concurrent list)
Supremacy of the constitution: article 6 of the US constitution says that the constitution of USA is supreme. In India, there is no such provision but, because of how the constitution evolved and because of the intention behind the making of the constitution it is considered as supreme. Till date, no state or party has refused to abide by it.
An empirical evidence that provides us with that the constitution of India is supreme is that there has been no challenge to the constitution. It has been established that the text and the spirit of constitution is supreme.
Dispute resolution mechanism: there should be a separate adjudicatory body for dispute resolution. In India, there is a clear distinction between an authority that acts as a dispute resolution mechanism. The supreme court of India acts as a dispute resolution authority . Its original jurisdiction comes from article 131 of the Indian constitution.
It can be said that India is a federal nation but with strong centralizing features. The Indian federalism is quite distinctive from the federalism with respect to the U.S.A. also to say, that we are not federal in comparison with USA.