Opposition proceedings in India:

Patent opposition in India is a vital safeguard under the Patents Act, 1970 that ensures only deserving inventions are granted and it is mechanism that allows the public to raise objections against the grant of a patent by filing an opposition with the Patent office.

There are 2 types of opposition proceedings in place depending on the stage of grant of the patent:

1. Pre-grant opposition: Where the opponent can challenge a pending application prior to the grant of a patent.

2. Post-grant opposition: Where the opponent challenges the validity of a patent that has already been granted. 

   
   

Pre-grant opposition in India

Section 25(1) of the Patents Act, 1970, read with Rule 55 of the Patents Rules, 2003, governs the framework for pre-grant opposition in India. A pre-grant opposition may be filed by any person, in writing, at any time after the publication of the patent application and before the grant of the patent.

For this purpose, it is essential to review the complete specification available on the official patent database, as an opposition cannot be effectively based on the abstract alone. This mechanism serves as a preventive safeguard, ensuring that only valid and deserving applications proceed to grant. The opposition at this stage is formally referred to as a “representation” before the Controller.

Grounds for pre-grant opposition

The grounds for pre-grant opposition are specifically provided under Section 25(1) of the Patents Act, 1970. A representation may be filed on the following grounds:

• The applicant has wrongfully obtained the invention from the opponent or another person

• The invention has been published prior to the priority date in India or elsewhere

• The invention has been publicly known or publicly used in India before the priority date

• The invention is obvious and lacks inventive step 

• The invention is not patentable subject matter under the Act (for example, falling under Section 3 exclusions)

• The complete specification does not sufficiently and clearly describe the invention or the method by which it is to be performed

• The applicant has failed to disclose required information under Section 8 or has furnished false information

• The application is not filed within the prescribed time in case of a convention application

• The specification does not disclose or wrongly mentions the source or geographical origin of biological material, if used

• The invention is anticipated by traditional knowledge or forms part of the known knowledge of any community

  
  

Procedure for pre-grant opposition

Pre-grant opposition can be filed under Rule 55 by any person after the publication of a patent application and any time before the grant of the patent.  The rule states that all representations for opposition must be made in accordance with Form 7A of the Act to the Controller General of Patents. There is no strict deadline other than ensuring it is filed prior to grant, which makes it a flexible and preventive remedy.

The process begins with filing a representation for opposition along with supporting evidence. The Controller then considers the representation and may forward it to the Applicant for response. The Applicant is given an opportunity to file a reply statement and evidence within 3 months, and if requested, a hearing may be conducted. Based on the submissions, the Controller considers the statements and issues a speaking order, which may:

• Grant the patent,

• Refuse the patent, and

• Require the amendment of the patent specification or other documents after which the patent can be granted.

Post-grant opposition in India

Once a patent has been granted, it may still be challenged by third parties through a post-grant opposition. This is initiated by filing a “notice of opposition” before the Controller of the appropriate patent office within 12 months from the date of publication of the grant in the Patent Journal.

Unlike pre-grant opposition, a post-grant opposition can only be filed by a “person interested.” As defined under Section 2(1)(t) of the Patents Act, 1970, the term is broad and includes any person engaged in, or promoting, research in the same field as the invention. It may also extend to entities having a commercial, manufacturing, trading, or financial interest in the patented product or process.

Grounds for Post-Grant Opposition

Under the Patents Act, 1970, there is no distinction between the grounds for pre-grant and post-grant opposition. Section 25(2) provides the same set of grounds as those specified under Section 25(1).

However, while the grounds remain identical, the procedures governing pre-grant and post-grant oppositions differ significantly, particularly in terms of formality, timelines, and evidentiary requirements, which are addressed separately.

Procedure for post-grant opposition

The process begins with filing a notice of opposition along with a statement and evidence. Upon receipt, the Controller constitutes an Opposition Board, which examines the case and provides recommendations. The Applicant is then required to file a reply statement and evidence (typically within 2 months), followed by the Opponent’s rejoinder evidence (within 1 month). After completion of pleadings, a hearing is conducted, and the Controller issues a reasoned decision. The entire post-grant opposition process generally spans 12–18 months, depending on the complexity of the case and timelines of hearings. The outcome may result in the patent being maintained, amended, or revoked.

Appeal

The decision of the Controller in both pre-grant and post-grant opposition proceedings may be challenged by way of an appeal within three months from the date of the order.

However, it is important to note that where a patent is granted despite a pre-grant opposition, the remedy of appeal lies before the High Court and not before the IPAB.

From a patent attorney’s advisory perspective, pre-grant and post-grant opposition mechanisms serve distinct yet complementary strategic functions. Pre-grant opposition operates as a proactive risk-filtering tool, enabling early-stage intervention to prevent the grant of patents that may adversely impact a client’s commercial interests. In contrast, post-grant opposition serves as a corrective and enforcement-stage remedy, allowing stakeholders to challenge patents that may have been granted despite legal or technical deficiencies.

As part of SCIP due diligence, it is essential for businesses to continuously monitor competitor filings, assess potential blocking patents, and evaluate opposition opportunities to safeguard their freedom to operate and market position. Equally, from an applicant’s standpoint, these mechanisms underscore the necessity of robust patent drafting, complete and accurate disclosure, and strict statutory compliance to withstand potential challenges.

In an increasingly competitive and innovation-driven environment, patent opposition should be viewed not merely as a procedural safeguard, but as a critical strategic tool that can significantly influence market entry decisions, investment evaluations, licensing strategies, and overall portfolio strength.

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