Testing a Patent: Opposition and Revocation in India


It is sometimes presumed that the patent application process concludes with the grant of a patent, after it has been successfully prosecuted. Although prosecution examines an application for patentability, its true test arguably comes during the opposition process. It would not be a stretch to suggest that patent opposition is as integral a part of the process of obtaining a patent, as is its prosecution.

Patent opposition refers to the legal procedure that allows for a third party to oppose or challenge the legitimacy of a pending patent application or a granted patent. This helps the patent office to grant quality patents. Like patent prosecution, patent opposition is also split into two parts:

  1. Pre-Grant Opposition
  2. Post-Grant Opposition

A pre-grant opposition is filed when an application for a patent has been published, but not granted. A post-grant opposition, as the name suggests, can be filed after the grant of a patent, however, this must be filed within 12 months of the publication of the grant of the patent. In fact, the Supreme Court in Alloys Wobben v. Yogesh Mehra, [C.A. No. 6718/2013] has laid down that it is only after opposition if any, is concluded in favour of the patentee, that rights can truly be said to have been crystallized.

The grounds for filing these oppositions have been clearly set out in Section 25 of the Act which include wrongful obtainment of patent, previously published, non-obvious, publicly used, etc. For pre-grant as well as post-grant oppositions, the grounds are almost identical, but with some procedural differences. A key difference is that any person can challenge a patent application at the pre-grant stage, but only an interested person can file a post-grant opposition. Section 2(1)(t) of the Act defines “person interested” as including a person engaged in, or in promoting, research in the same field as that to which the invention relates. Additionally, although the Indian Patents Act, 1970 (the Act) indicates that any person can file a pre-grant opposition, following recent jurisprudence, it is recommended that only a person who is involved in the field of technology of the patent in question file a pre-grant opposition. Habitual opposers that merely delay the grant of patents have made courts wary of oppositions filed by third parties who are unable to demonstrate any connection with the patent technology. For example, the Bombay High Court in Dhaval Diyora v. Union of India [W.P.(L) No. 3718/2020] criticised that the credentials of the petitioner, including his educational background, had not been made known, and dismissed the writ petition, concluding that the petitioner was nothing but a habitual frontman. This was followed also in the IPAB decision of Novartis AG v. Controller General of Patents & Ors. [OA/1/2021/PT/DEL].

When an opposition is filed, the Controller of the Patent Office generally fixes a date of hearing and then informs both parties about the same. If the opposition succeeds, the conclusion is also notified to both parties, following which the patent application is refused.

Revocation of a Patent 

Revocation is essentially an act of taking away or cancelling the patentee’s rights over a granted patent. Its grounds are laid down in Section 64 of the Act, and include lack of novelty, lack of inventive step, no industrial applicability, existence of prior art, not useful, and insufficiency, among others. The Central Government can also revoke a patent if it is of the opinion that the patent goes against public interest. A key ground for revocation that is not available as a ground for opposition is that of non-working of a patent, under which if a patent has not been worked over time, it is liable to be revoked. A patent can be revoked by a petition filed by any person interested, or in an infringement suit that has been initiated by means of a counterclaim.


Although opposition and revocation proceedings are opportunities for the public to challenge and prevent the grant of ill-considered patents, the opposition of a patent serves as the more efficient route, for multiple reasons. Not only are the fees for pursuing an opposition lower than that for revocation, but also, in revocation proceedings initiated in infringement suits, the cases can go on for a long time until decided by the courts, potentially leaving contesting parties in limbo until then. Once a patent passes the test of opposition, it obtains a higher value since it overcomes challenges. In the long run, such proceedings also help develop and better the patent system at large, by encouraging quality patent grants and preventing frivolous patents.