Which doctrine was abolished by Section 6(4) of the Hindu Succession Act, 1956 (as amended in 2005), so…

Section 6(4) of the Hindu Succession Act, 1956, as substituted by the Hindu Succession (Amendment) Act, 2005, abolishes the "Doctrine of pious obligation": no court shall recognise any right to proceed against a son, grandson or great-grandson for a debt of his father, grandfather or great-grandfather solely on the ground of that obligation. Under the proviso, debts contracted before the 2005 amendment came into force can still be enforced. Survivorship is dealt with separately in Section 6(3), and the right by birth was not abolished but extended to daughters.