Explanation:

 Constitution Day (National Law Day), also known as Samvidhan Divas, is celebrated in India on 26 November every year to commemorate the adoption of Constitution of India. On 26 November 1949, the Constituent Assembly of India adopted the Constitution of India, and it came into effect on 26 January 1950.
The Constitution was adopted by the Indian Constituent Assembly on 26 November 1949, and came into effect on 26 January 1950 with a democratic government system, completing the country's transition towards becoming an independent republic. 26 January was chosen as the Republic day because it was on this day in 1930 when Declaration of Indian Independence (Purna Swaraj) was proclaimed by the Indian National Congress as opposed to the Dominion status offered by British Regime.
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•The Beating Retreat ceremony is held after officially denoting the end of Republic Day festivities. It is conducted on the evening of 29 January, the third day after the Republic Day. It is performed by the bands of the three wings of the military, the Indian Army, Indian Navy and Indian Air Force. The venue is Raisina Hill and an adjacent square, Vijay Chowk, flanked by the North and South block of the Rashtrapati Bhavan (President's Palace) towards the end of Rajpath. The Chief Guest of the function is the President of India who arrives escorted by the (PBG), a cavalry unit.

THINK! •?Army Day, Navy Day and Air force Day.