The Constituent Assembly adopted the Constitution of India drafted by a committee headed by Dr. B. R. Ambedkar on 26 November 1949. Preamble was enacted on 26 November 1949 along with some other Articles rest of the constitution came into effect from 26 January 1950.

(a) Union of States: This means that India is a federation comprising states and union territories. It emphasizes the unity of the country while recognizing the diversity and autonomy of its states.

(b) Federal State with Unitary Features: India operates as a federal state where power is divided between the central government and individual states. However, there are certain unitary features, such as a strong central authority in matters like defense and national security.

(c) Federal State with Federal Features: This is not a term used to describe the Indian political system. India is often termed as a federal state with unitary features.

(d) Federal State: This term generally implies a political entity where power is shared between a central government and regional entities. India is indeed a federal state where states have their own governments and certain powers, alongside a strong central government.

Under Article 1, India is described as a “Union of States”. Federal word is not mentain in our constitution.