The 26th of January was chosen to honor the memory of the declaration of independence of 1930. It is one of the three national holidays in India. While the main parade takes place in the national capital New Delhi at the Rajpath before the president, the anniversary is also celebrated with varying degrees of formality in state capitals and other centres.
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.
The amending mechanism was lauded even at the time of introduction by Ambedkar in the following words: "We can therefore safely say that the Indian federation will not suffer from the faults of rigidity or legalism. Its distinguished feature is that it is a flexible federation.
"The three mechanisms of the system derived by the Assembly, contrary to the predictions, have made the constitution flexible at the same time protected the rights of the states. They have worked better than the amending process in any other country where Federalism and the British Parliamentary system jointly formed the basis of the constitution."