The 42nd amendment to Constitution of India, officially known as The Constitution (42nd Amendment) Act, 1976, was enacted during the Emergency (25 June 1975 – 21 March 1977) by the Indian National Congress government headed by Indira Gandhi.
The Indian Constitution: Political Development and Decay
Most provisions of the amendment came into effect on 3 January 1977, others were enforced from 1 February and Section 27 came into force on 1 April 1977.