Section 64 of the Patents Act says that a patent can be revoked by (i) the Appellate Board on the petition of any person interested, or the Central Government (ii) the High Court on a counter claim in an infringement suit.
A ‘person interested’ has been defined in Section 2 (t) of the Act. Also, in Ajay Industrial Corporation v. Shiro Kanao of Ibaraki City (AIR 1983 Del. 496), a ‘person interested’ was defined as ‘a person who has a direct, present and tangible commercial interest which is injured or affected by the continuance of the patent on the register’.
A High Court on the Central Government’s petition may revoke a patent if the patentee fails to comply with a request under Section 99 of the Act (for the use of the patent for Government purposes) without reasonable cause.
A notice of any petition for the revocation of a patent under Section 64 must be served on all persons appearing on the register as proprietors of the patent or to have shares or interests therein and it is not necessary to serve notice on any other person.

Grounds of Revocation of a Patent
1. that the invention has been claimed in a valid claim of any patent granted in India with an earlier priority date
2. that the patent was granted on the application of a person not entitled to apply for it
3. that the patentee wrongfully obtained the patent in contravention of the petitioner’s rights or a person under / through whom he claims
4. that the subject of any claim is not an invention
5. that the invention is not new having regard to (a) what was publicly known or used in India before the priority date (b) the publication in India or elsewhere of documents referred to in Section 13 related to the invention *
6. that the invention is obvious or involves no inventive step, with regard to what was publicly known or used in India before the priority date *
7. that the complete specification does not completely or fairly describe the invention
8. that the complete specification does not disclose the best manner of performing what has been patented known to the patentee for which he was entitled to claim protection
9. that the scope of any claim in the complete specification is not clearly defined
10. that any claim in the complete specification is not fairly based on matter disclosed in the complete specification
11. that the patent was obtained in false suggestion / representation
12. that the subject of any claim is not patentable
13. that the invention was secretly used in India before the priority date unless the used was (a) for reasonable trial or experiment (b) by the government, any person authorized by the government or a government undertaking or (c) by any other person.
If the use is by the Government, any person authorized by the government or a government undertaking, it must be in consequence of the disclosure or communication of the invention to the Government, any person authorized by the government or a government undertaking by the applicant for the patent or any other person from whom he derives title.

If the use is by any other person, it must be in consequence of the applicant for the patent or any person from whom he derives title having disclosed or communicated the invention, and without the consent or acquiescence of f the applicant for the patent or any person from whom he derives title.
14. that the information required to be disclosed under Section 8 was not disclosed
15. that the applicant knowingly furnished false information in regard to any material particular
16. that the applicant contravened any direction for secrecy made under Section 35 of the Act
17. that the applicant made an application in a foreign country against Section 39 of the Act
18. that leave to amend the complete specification under Section 57 or 58 of the Act was obtained by fraud
19. that the source or origin of biological material not disclosed or wrongly disclosed in the complete specification
20. that the invention was anticipated considering oral or other knowledge within an indigenous or local community within India or elsewhere.

* No notice is to be taken of a person document, secret trial, secret use, if a product made by a process was imported into India for reasonable trial / experiment only.

Revocation of a Patent or Amendment of a Complete Specification on Direction from the Government in Cases related to Atomic Energy
Under Section 65, where at any time after the grant of a patent, the Central Government is satisfied that a patent is for an invention relating to atomic energy for which a patent cannot be granted under the Atomic Energy Act, 1962, it may direct the Controller to revoke the patent. The Controller may then give notice to the patentee and all the persons who appear on the register as having an interest in the patent, and after giving them an opportunity to be heard, he may revoke the patent.

Revocation of a Patent in Public Interest
Under Section 66, where the Central Government is of the opinion that a patent or the mode in which it is exercised is mischievous to the State or generally prejudicial to the public, it may, after giving the patentee an opportunity to be heard, make a declaration to that effect in the Official Gazette and thereupon the patent shall be deemed to be revoked.