Patent Opposition in India: Pre-Grant vs Post-Grant Under Section 25

Section 25 of the Patents Act, 1970 gives a third party two distinct windows to challenge an Indian patent. Section 25(1) is the pre-grant opposition, available any time after publication of the application and before grant. Section 25(2) is the post-grant opposition, available within twelve months of the grant. The two run on different rules, different forums and different evidentiary standards. They are also the most common pre-litigation mechanism Indian generics, competitors and public-interest groups use to delay or defeat questionable patents — most famously, in the lead-up to the Novartis Glivec litigation.

This guide covers the procedural differences, the standing rules, the grounds available under each provision, and the strategic choice between them.

Pre-grant opposition under Section 25(1)

Standing is broad. Any person may file a pre-grant opposition — including individuals, NGOs and trade associations, not only commercial competitors. The opposition is filed in Form 7A with no government fee. It can be filed at any time after the application is published under Section 11A and before grant.

The Controller of Patents considers the representation, gives the applicant an opportunity to respond, and decides whether to hold a hearing. If the opposition succeeds, the application is refused. If not, the application proceeds to grant. There is no formal appellate forum at this stage — the applicant's remedy is to continue prosecution after refusal; the opponent's remedy if the patent is granted is to file a post-grant opposition or a revocation petition.

Pre-grant is the cheapest way to stop a patent in India. No fee, no standing barrier, and it sits in the same office that grants the patent.

Post-grant opposition under Section 25(2)

Post-grant has narrower standing — only a "person interested" may file. The Patents Act defines a "person interested" broadly to include anyone whose interests are or may be affected by the patent — typically competitors in the same technical field, generic manufacturers in pharma matters, and downstream users. The opposition is filed in Form 7 with a fee, within twelve months of the date of grant published in the Patent Journal.

The post-grant opposition is heard by an Opposition Board of three Examiners constituted by the Controller. The Board examines the case, conducts a hearing where both sides are heard, and makes a recommendation. The Controller passes a reasoned order based on the Board's recommendation. Outcomes are: patent maintained as granted, maintained in amended form, or revoked.

Grounds available under Section 25

The grounds available under 25(1) and 25(2) are largely the same — both sub-sections list eleven grounds, including:

• (a) Wrongful obtainment — the applicant obtained the invention from the opponent
• (b) Prior publication — invention published before the priority date
• (c) Prior claiming — invention claimed in an earlier published Indian application
• (d) Prior public knowledge / use in India
• (e) Obviousness — invention obvious in light of prior art
• (f) Not an invention within Sections 3 and 4 — Section 3(d), 3(j), 3(k), method-of-treatment exclusions all live here
• (g) Insufficiency — specification does not sufficiently and clearly describe the invention
• (h) Failure to disclose information required under Section 8 (foreign filings)
• (i) Convention application filed beyond the 12-month period
• (j) No proper traditional-knowledge disclosure
• (k) Anticipated by traditional knowledge of any community

Strategic choice: pre-grant or post-grant?

Both routes attack the same patent on the same grounds. The strategic differences are timing, cost and process:

• Pre-grant is cheaper — no fee, no Form 7 cost, simpler proceedings. It is also the only route open to a non-commercial opponent who lacks "person interested" standing.
• Pre-grant blocks the patent ever issuing — useful for generics planning launch, for whom even a granted-then-revoked patent creates risk during the gap.
• Post-grant has a structured Opposition Board hearing — more rigorous procedure, more chances to put evidence on record, but a higher cost-of-attempt.
• Post-grant deadlines are absolute — twelve months from grant. Miss it and the only remaining route is a revocation petition under Section 64 in the High Court.

Procedural realities — what to expect

Pre-grant oppositions in India tend to extend prosecution by 12-24 months. The Controller usually allows the applicant a response, sometimes multiple, and there can be a hearing. For a generic manufacturer planning a launch after compound-patent expiry, this delay is itself the win — it pushes back the grant date, shrinks the term remaining, and creates uncertainty during which a parallel revocation strategy can be built.

Post-grant proceedings before the Opposition Board run 12-24 months on average, sometimes longer in complex pharma or biotech matters. The Board's recommendation is technically advisory, but Controllers seldom depart from it in practice. The reasoned order is appealable to the High Court under Section 117A.

Revocation as the alternative

If both opposition windows have closed, the only route remaining is a revocation petition under Section 64, filed in the relevant High Court. Standing is again restricted to a "person interested". The grounds overlap heavily with Section 25 but include additional ones — fraud, lack of utility, failure to work the invention in India (Section 84-related), and a few others. Revocation is more expensive and slower than opposition, but it is the only post-opposition route open.

The takeaway

For competitors, generics and public-interest opponents in India, Section 25 offers two real, structured chances to defeat a patent without going to court. Pre-grant under 25(1) is the broad-standing, low-cost option that has stopped many questionable applications at the Patent Office stage. Post-grant under 25(2) is the structured, evidence-heavy option that has revoked many granted patents in their first year. Choosing between them is a question of standing, timing and budget — not of substantive grounds, which are largely identical. IPForte's patent prosecution team files both routinely, and runs the parallel watching-and-opposition strategy that generics need before a launch window.