- Fundamental Duties were added to the Constitution by the 42nd Amendment Act, 1976. - The Keshvanand Bharti case (1973) is a landmark judgment that established Parliament's power to amend Fundamental Rights, but also introduced the 'Doctrine of Basic Structure' as a limitation on this power. - The Doctrine of Basic Features (or Basic Structure) was propounded in the Keshvanand Bharti case. The Minerva Mills case (1980) further applied and reinforced this doctrine, particularly in striking down parts of the 42nd Amendment. While Keshvanand Bharti originated the doctrine, Minerva Mills is a significant case in its evolution and application. - Article 23 of the Constitution of India prohibits traffic in human beings and forced labour.