A decree obtained by fraud cannot be used as res judicata and the same can be challenged by a separate Suit-SC-RAM CHANDRA SINGH VS
SAVITRI DEVI AND OTHERS - judiciary in India also possesses inherent power, specially u/s 151 CPC, to recall its judgment or order if it is obtained by fraud" on Court, In the case of fraud on a party to the suit or proceedings, the Court may direct the affected party to file a separate suit for setting aside the decree obtained by fraud. Inherent powers are powers, which are resident in all Courts, especially of superior jurisdiction. These powers spring not from legislation but from the nature and the constitution of the tribunals or Courts themselves so as to enable them to maintain their dignity, secure obedience to its process and rules, protect its officers from indignity and wrong and to punish unseemly behavior. This power is necessary for the orderly administration of the Court's business.
Bhagwati Prasad Versus Chandramaul- 19/10/1965-If a party asks for a relief on a clear and specific ground, and in the issues or at the trial, no other ground is covered either directly or by necessary implication, it would not be open to the said party to attempt to sustain the same claim on a ground which is entirely new.