The exact constitutional status of India on 26th January 1950 was a Sovereign Democratic Republic.

• The Constitution of India was adopted on 26th November 1949, but it came into effect on 26th January 1950.
• The Preamble of the Constitution, adopted in 1949, defined India as a "Sovereign Democratic Republic."
• The terms "Socialist" and "Secular" were added to the Preamble much later, through the 42nd Amendment Act of 1976.

Therefore, on 26th January 1950, India wasn't yet classified as "Socialist" or "Secular" in its constitution.