Post-grant opposition and revocation proceedings under Indian Patent Act: what is better?

Patent Act, 1970 provides opposition/ revocation mechanisms to make sure that undeserving Patents are not granted in contravention of the provisions of the Act and if they are granted, they can be opposed/ revoked. Grant of patent can be opposed before as well as after grant of patent. Relevant sections for different mechanisms, locus standi, jurisdictions where they can be entertained, timelines within which they can be opted, and the grounds on which they can be based have been summarized in the below table:

When we carefully analyse the mechanisms, it is evident that post-grant opposition gets stricter than pre-grant. However, down the time after grant, story again changes wherein in revocation, locus standi is also provided to central government, timeline for revocation is not restricted to 1 year after publication of grant and also the words ‘but on no other ground’ which appear in 25 (1) and 25 (2), do not appear in section 64. Absence of these words can be construed to mean section 64 does not require person to stick to the grounds provided by section 64 like section 25 (1) and section 25 (2) do.

Further observation also indicates that standard of obviousness required to oppose the patent during post-grant opposition is higher than that required during revocation.

Section 25 (2) (e) and section 64 (f) has been reproduced below:

Section 25 (2) (e): that the invention so far as claimed in any claim of the complete specification is obvious and clearly does not involve any inventive step, having regard to the matter published as mentioned in clause (b) or having regard to what was used in India before the priority date of the claim;

section 64 (f)

that the invention so far as claimed in any claim of the complete specification is obvious or does not involve any inventive step, having regard to what was publicly known or publicly used in India or what was published in India or elsewhere before the priority date of the claim:

It can be seen that section 64(f) unlike section 25 (2) (e) does not require invention to be clearly not involving any inventive step. Interestingly section 64 not only allows other grounds than those provided by section 64 to be used in the revocation, it also provides more/ additional grounds than those provided by section 25 (2).

While it is clear that revocation at high court cannot be chosen unless patentee has asserted patent infringement, revocation at IPAB can be chosen any time after grant and even when patentee has not asserted infringement. Patent revocation cannot be sought once proceedings for patent opposition under section 25 (2) have been initiated and are pending. Therefore, one has to clearly think of the advantages revocation proceedings provide over post-grant proceedings.