An application to SET ASIDE an arbitral award under the Arbitration and Conciliation Act, 1996 must be made under which section, and ordinarily within what time?

Section 34 is the exclusive remedy to challenge a domestic arbitral award; a party may apply to set it aside on the limited grounds it enumerates - incapacity, invalid arbitration agreement, want of proper notice, award beyond the scope of reference, composition/procedure opposed to the party's agreement, or conflict with the public policy of India. The application must be made within three months of receiving the award, with a further discretionary thirty days for sufficient cause under the proviso. A valid Section 34 application is the gateway that prevents automatic enforcement; execution otherwise proceeds under Section 36.