The Republic Day of India commemorates the date on which the Constitution of India came into force replacing the Government of India Act 1935 as the governing document of India on 26 January 1950.
Although India obtained its independence on 15 August 1947, it did not yet have a permanent constitution; instead, its laws were based on the modified colonial Government of India Act 1935, and the country was a Dominion, with George VI as head of state and Earl Mountbatten as Governor General. On 28 August 1947, the Drafting Committee was appointed to draft a permanent constitution, with Bhimrao Ramji Ambedkar as chairman. While India's Independence Day celebrates its freedom from British Rule, the Republic Day celebrates the coming into force of its constitution.
A draft constitution was prepared by the committee and submitted to the Assembly on 4 November 1947. The Assembly met, in sessions open to public, for 166 days, spread over a period of 2 years, 11 months and 18 days before adopting the Constitution. After many deliberations and some modifications, the 308 members of the Assembly signed two hand-written copies of the document (one each in Hindi and English) on 24 January 1950. Two days later, the Constitution of India became the law of all the Indian lands. The Constitution of India was passed on 26 November 1949, 10.18 AM IST, but it came into effect completely only on 26 January 1950. Following elections on 21 January 1950, Rajendra Prasad was elected as the president of India. The Indian National Congress and other parties had been celebrating 26 January as a symbol of Independence, even before India actually became independent. Thus, applying the constitution on 26 January, to mark and respect 26 January and the freedom struggle and the freedom fighters.