Finally, the Indian Constitution was approved on 26th of November, 1949 and came into force on 26th of January, 1950. This day (January 26) is celebrated as the 'Republic Day' in India.

The Constitution of India was formed through a process of formation of constituent assembly which drafted, debated, deliberated, amended and finally formed a final Constitution of India. ... The Constitution was adopted finally in Nov. 1949 with the seal of the Constituent assembly of India.