Question

what makes india a federal system

Answer 1

division of powers; the constituion divides power between union and state goverment by three lists - union list , state list and concurrent list. amendments of the constituion makes India a federal country.

Answer 2

It is a system of government in which entities such as states or province share power with central government.

In India there have various states so that the power couldn't be control by the single government. Hence, we need a government which would share power with central government. The federation helps to enjoy the power on different tier of government. Every tiers of government have separate jurisdiction which makes easier to deal with laws.

The Indian Government clearly provided threefold distribution of legislative powers between union government and state government which contains three lists:-

Union list
State list
concurrent list

Now,coming to your question,

We all know that India is vast country which have various languages,religions and regions. Which should be control through the federalism . It can't be control through single government . Thus,the India needs federal government which needs power sharing.