Patent Opposition in India: Pre-Grant vs Post-Grant and What Each Actually Requires

An engineering company is preparing to launch a new industrial process it has spent three years developing. During a routine patent search ahead of the launch, the team identifies a competitor’s patent application, published but not yet granted, that covers a process step central to how the product works. The application is still pending. At this point, the company has two choices: challenge the application now, before the patent is granted, or wait and challenge the granted patent afterward.

The choice is not just a matter of timing. Pre-grant and post-grant opposition are structurally different proceedings, with different standing requirements, different procedural burdens, different strategic implications, and since a 2024 amendment to the Patents Rules, a different relationship between the initial filing and the actual substantive challenge. Getting this choice wrong can mean either missing the most efficient window to stop a patent or spending resources on a proceeding that does not deliver the commercial outcome the business needed, which is why it is usually the first strategic question an IPR law firm works through with a client facing a competing patent.

The Two Mechanisms: What the Act Actually Provides

Both pre-grant and post-grant opposition sit under Section 25 of the Patents Act, 1970. Pre-grant opposition is governed by Section 25(1), post-grant opposition by Section 25(2). The grounds available under both are substantially similar, covering lack of novelty, obviousness, non-patentable subject matter, insufficient disclosure, and in the pharmaceutical context, failure to meet the Section 3(d) threshold for new forms of known substances.

The structural differences between the two routes are what matter for strategy.

Pre-Grant Opposition: Who Can File and When

A pre-grant opposition can be filed by any person using Form 7A under Rule 55 of the Patents Rules, 2003. There is no requirement to demonstrate a direct commercial interest in the outcome. A competitor, an industry association, a public interest organisation, or any individual can file a representation opposing the grant of a patent application after it has been published in the Official Journal of the Patent Office.

The window for filing is open from the date of publication of the application until the date the patent is actually granted. There is no fixed deadline within that window, which gives opponents flexibility to monitor the application’s progress through examination before deciding when to file. The window closes the moment the patent is granted: once grant occurs, pre-grant opposition is no longer available and the only remaining route is post-grant opposition or a revocation action.

Under Rule 55(1A), a patent cannot be granted before the expiry of six months from the date of publication of the application under Section 11A. Further, under amended Rule 55(5B), where a pre-grant opposition representation has been filed and the Controller has issued the prescribed notice, the application is examined in accordance with Rule 24C, which governs expedited examination.

The 2024 Rule Change: What It Means in Practice

The Patents (Amendment) Rules, 2024, notified on 15 March 2024, introduced changes to the pre-grant opposition process that significantly affect how these proceedings work.

Following the Patents (Amendment) Rules, 2024, a pre-grant opposition representation is subject to preliminary scrutiny by the Controller to determine whether a prima facie case has been established. Where no prima facie case is found, the opponent is notified and may request a hearing. If no hearing is requested, the Controller is required to pass a reasoned order refusing the representation within the prescribed period. Where a prima facie case is established, the Controller proceeds in accordance with Rule 55, including notification to the applicant and consideration of the applicant's response. Further, a pre-grant opposition representation is considered only after a request for examination of the patent application has been filed.

The Patents (Amendment) Rules, 2024 introduced an official filing fee for pre-grant opposition representations under Form 7A. The prescribed electronic filing fee is INR 4,000 for eligible natural persons, startups, small entities and educational institutions, and INR 20,000 for other entities, subject to the applicable fee classification and filing requirements under the First Schedule. Previously, no official fee was payable.

What this means practically: filing a pre-grant opposition is no longer simply a matter of putting an objection on record. The representation should clearly identify the applicable statutory grounds and provide supporting technical, documentary, or other evidence, as appropriate to those grounds. Where novelty or inventive step is challenged, the opponent should identify relevant prior-art references and explain their relationship to the claims. For other grounds, such as insufficient disclosure, non-patentability, or wrongful obtaining, the representation should provide corresponding legal and factual reasoning sufficient to establish a prima facie case.

For the engineering company in the scenario above, this means the pre-grant filing needs to identify the specific prior art document, whether a published patent, a technical paper, or a product that predates the application, and demonstrate precisely how it anticipates the claims being challenged.

Post-Grant Opposition: Standing, Timeline, and Process

Post-grant opposition is more formal and carries a stricter standing requirement. Under Section 25(2), only a “person interested” can file a post-grant opposition using Form 7. The Act defines a person interested as including persons engaged in, or promoting, research in the same field as the patent. In practice, this typically means a commercial competitor in the relevant technology or product category, or someone with a demonstrable stake in the outcome.

The filing window is fixed: a post-grant opposition must be filed within one year from the date of publication of the grant of the patent. Miss this window and the only remaining route to challenge the patent is a revocation petition before the High Court, which is a different and generally more resource-intensive proceeding.

Once filed, post-grant opposition follows a structured sequence. The Controller constitutes an Opposition Board comprising three members and nominates one member as Chairman. An examiner appointed under Section 73(2) may serve on the Board, provided that the examiner did not deal with the patent application during the proceedings leading to grant. The opponent files evidence in support of the opposition, following which the patentee may file a reply statement and evidence. The opponent may subsequently file reply evidence in accordance with the prescribed rules. The Board examines the opposition and supporting documents and submits its reasoned recommendations within two months from the date on which the relevant documents are forwarded to it. After considering the Board's recommendations and hearing the parties in accordance with the prescribed procedure, the Controller may order that the patent be maintained, amended, or revoked.

The duration of post-grant opposition proceedings may vary depending on the complexity of the matter, the evidence submitted, and the Patent Office's schedule. Post-grant opposition provides a structured statutory mechanism for challenging an already granted patent, including examination by an Opposition Board and a reasoned determination by the Controller. An order passed under Section 25(4) is appealable before the High Court in accordance with Section 117A of the Patents Act, 1970.

The Core Strategic Question: Which Route and When

The choice between pre-grant and post-grant opposition depends on timing, commercial stakes, and what the opponent needs to achieve.

Pre-grant opposition makes the most sense when the patent application is still pending and the opponent has clear prior art or a strong technical argument that can be placed on record before grant. For companies planning a product launch that would be blocked by a pending patent, successfully opposing the application at the pre-grant stage can mean the difference between launching on time and facing an injunction. The engineering company that identified a conflicting application before its product launch is in exactly this position: Successfully opposing the application before grant can prevent enforceable patent rights from arising from that application in the form opposed, thereby reducing the risk of infringement proceedings based on those claims. However, other granted patents, related applications, or subsequently arising patent rights may still affect the company's freedom to operate.

Post-grant opposition is the appropriate route when the patent has already been granted and the opponent needs a formal, legally binding determination of validity. A business that discovers a competitor’s recently granted patent threatens its existing commercial activity uses the post-grant route to challenge the granted right with the full procedural weight of an Opposition Board proceeding.

One point that is frequently overlooked: there is no prohibition on filing both. A party that files a pre-grant representation and does not succeed in stopping the grant can subsequently file a post-grant opposition within the one-year window. In high-value technology and pharmaceutical disputes, both routes are sometimes used in sequence.

Grounds That Carry the Most Weight

The most relevant grounds depend on the technology and the nature of the patent being challenged.

For pharmaceutical patents, Section 3(d) is frequently the most consequential ground: a secondary patent on a new salt, polymorph, or formulation of a known drug compound can be challenged on the basis that the new form does not show significantly enhanced therapeutic efficacy. For engineering, chemical, and technology patents, anticipation by prior art and obviousness carry the most weight. An opposition that identifies a specific published patent, technical paper, or product documentation that precisely anticipates the claimed invention is far stronger than one that makes broad arguments without anchoring them to specific prior art documents.

Insufficient disclosure is a ground available across all technology areas: if the patent specification does not describe the invention clearly enough for a skilled person to reproduce it, that is a standalone basis for challenge regardless of what the invention covers.

What Happens After Opposition

The outcome of an opposition depends on the grounds established and the Controller's determination. In pre-grant opposition proceedings, the Controller may reject the representation, require amendments to the specification or claims before grant, or refuse to grant the patent. In post-grant opposition proceedings, the Controller may maintain, amend, or revoke the patent under Section 25(4) of the Patents Act, 1970. Accordingly, an opposition may result in refusal or revocation, or in a narrower scope of patent protection following permissible amendments.

An unsuccessful opposition does not necessarily prevent a subsequent challenge to the patent. Subject to the applicable statutory and procedural requirements, a person interested may seek revocation of a patent before the High Court under Section 64 of the Patents Act, 1970. Patent validity may also be challenged through a counterclaim in infringement proceedings. However, the availability and prospects of such remedies depend on the applicable grounds, evidence, and circumstances of the case. Therefore, the quality of the initial opposition filing remains important regardless of which route is chosen.

M&P IP Protectors advises engineering, technology, chemical, pharmaceutical, and manufacturing companies on patent protection strategy in India, including pre-grant and post-grant opposition proceedings. To assess whether a pending or granted patent can be challenged, and which route best fits the commercial situation, speak with our patent attorneys.