Independence Day is celebrated annually on 15 August as a national holiday in India commemorating the nation's independence from the United Kingdom on 15 August 1947, the day when the provisions of the 1947 Indian Independence Act, which transferred legislative sovereignty to the Indian Constituent Assembly, came into effect.
India retained King George VI as head of state until its transition to a republic, when the nation adopted the Constitution of India on 26 January 1950 (celebrated as Indian Republic Day) and replaced the dominion prefix, Dominion of India, with the enactment of the sovereign law Constitution of India.

The Constituent Assembly of India met for its fifth session at 11 pm on 14 August in the Constitution Hall in New Delhi. The session was chaired by the president Dr. Rajendra Prasad. In this session, Jawaharlal Nehru delivered the Tryst with Destiny speech proclaiming India's independence.

Long years ago we made a tryst with destiny, and now the time comes when we shall redeem our pledge, not wholly or in full measure, but very substantially. At the stroke of the midnight hour, when the world sleeps, India will awake to life and freedom. A moment comes, which comes but rarely in history when we step out from the old to the new when an age ends, and when the soul of a nation, long suppressed, finds utterance. It is fitting that at this solemn moment, we take the pledge of dedication to the service of India and her people and to the still larger cause of humanity.
— Tryst with Destiny speech, Jawaharlal Nehru, 15 August 1947

The members of the Assembly formally took the pledge of being in the service of the country. A group of women, representing the women of India, formally presented the national flag to the assembly.

Independence Day, one of the three National holidays in India (the other two being the Republic Day on 26 January and Mahatma Gandhi's birthday on 2 October), is observed in all Indian states and union territories. On the eve of Independence Day, the President of India delivers the "Address to the Nation". On 15 August, the Prime Minister hoists the Indian flag on the ramparts of the historical site of Red Fort in Delhi.[26] Twenty-one gun shots are fired in honour of the solemn occasion.[27] In his speech, the Prime Minister highlights the past year's achievements, raises important issues and calls for further development. He pays tribute to the leaders of the Indian independence movement. The Indian national anthem, "Jana Gana Mana", is sung. The speech is followed by a march past of divisions of the Indian Armed Forces and paramilitary forces. Parades and pageants showcase scenes from the independence struggle and India's diverse cultural traditions.

Similar events take place in state capitals where the Chief Ministers of individual states unfurl the national flag, followed by parades and pageants.

Flag hoisting ceremonies and cultural programmes take place in governmental and non-governmental institutions throughout the country.Schools and colleges conduct flag hoisting ceremonies and various cultural events. Governmental and non-governmental institutions decorate their premises with paper, balloon decorations with hangings of freedom fighter portraits on their walls and major government buildings are often adorned with strings of lights.
In Delhi and some other cities, kite flying adds to the occasion.

National flags of different sizes are used abundantly to symbolise allegiance to the country.Citizens adorn their clothing, wristbands, cars, household accessories with replicas of the tri-colour. Over a period of time, the celebration has changed emphasis from nationalism to a broader celebration of all things India.