India cannot be a unitary state because the constitution gives more power to center than the states,more power is given to central government.Here’s an explanation for more clarity-

1-India is a diverse country and home of vast cultures,languages,ethnic groups and religions,if all the power will be centralised it would be difficult for a government to manage and respect the diversity,hence the federal structure gives different states the authority to manage things according to their local needs.

2-In British era,India was controlled by a centralised authority,which caused a lot of dissatisfaction and the framers of the constitution were aware about this situation hence they designed our constitution accordingly.

3-The federal structure of our constitution divides the power between central and state.India has bicameral legislature which represents the states at the federal level.

4-The center has more powers but supreme court often rules in favour of states rights whenever there is conflict which maintains power between center and state.

5-India is large and diverse country it cannot be government effectively by centralised authority and centralised government would be overburdened and disconnected from local realities ,local administration are better at handling local issues which helps in smooth functioning.

In simpler terms,India should remain a federal country because it is too diverse and has complex historical context and need for local governance.The balance between federalism and centralisation ensures effective functioning of a nation while respecting regional identities and maintaining unity.