The Preamble was adopted by the Constituent Assembly on November 26, 1949, along with the rest of the Constitution, though most provisions came into force on January 26, 1950.

Constitution adoption timeline: (a) November 26, 1949: Constituent Assembly adopted Constitution including Preamble; this date celebrated as Constitution Day, (b) January 26, 1950: Constitution came into force (chosen to honor 1930 Purna Swaraj declaration), (c) Transitional provisions: Some provisions (citizenship, elections, provisional Parliament) came into force November 26, 1949 for transitional arrangements, (d) Historical context: (i) Preamble drafting: Inspired by Objectives Resolution moved by Nehru (1946), refined through Constituent Assembly debates, (ii) 'We the people': Asserts popular sovereignty, distinguishes from colonial-era laws, (iii) Values selection: Justice, liberty, equality, fraternity reflect Constituent Assembly's vision for post-colonial India, (e) Symbolic significance: (i) November 26: Completion of constitution-making, (ii) January 26: Assertion of democratic sovereignty, (f) Illustrates constitutional founding: Preamble as expression of collective will, foundational values for new republic. Essential for UPSC Prelims factual knowledge and Mains conceptual understanding.