Question

maintain the date and year from which constitution of India start functioning

Answer 1

It was adopted by the Constituent Assembly of India on 26 November 1949, and became effective on 26 January 1950. The constitution replaced the Government of India Act, 1935 as the country's fundamental governing document, and the Dominion of India became the republic of India.

Answer 2

It imparts constitutional supremacy (not parliamentary supremacy, since it was created by a constituent assembly rather than Parliament), and was adopted by its people with a declaration in its preamble. ... It was adopted by the Constituent Assembly of India on 26 November 1949, and became effective on 26 January 1950.