But why is Republic Day so significant in modern Indian history? Republic Day is celebrated on January 26, marking the date when the Indian Constitution came into effect, completing India’s transition to becoming an independent republic. Find out why 26 January is celebrated as Republic Day in India. Learn its history, significance, and how people celebrate this day across the country. Republic Day in India, observed on January 26th, celebrates the transformation of India from a British Dominion to a democratic republic. January 26, Republic Day is a national holiday in India commemorating the adoption of the Constitution of the Republic of India and the country's transition to a republic which came into effect on 26 January 1950.