Constituent Assembly adopted Indian Constitution on November 26, 1949, but it came into effect on January 26, 1950. The day was chosen as the official enactment date to mark 'Purna Swaraj' declaration. Indian National Congress, at its 1929 Lahore session, passed a resolution, demanding 'Purna Swaraj' from British and asking people to observe January 26, 1930 as 'Purna Swaraj Day'.