Essential Grounds for Opposing Patent Applications and Grants

Not every patent application deserves to become a patent. That might sound obvious, but the challenge lies in building a system robust enough to catch undeserving claims before – or even after – they get granted. India’s patent law addresses this through a structured opposition mechanism under Section 25 of the Patents Act, 1970, which lays out specific grounds on which any third party can formally object to a patent application or an already-granted patent. These grounds are not arbitrary; they represent the foundational principles of patentability – novelty, inventive step, and adequate disclosure – and serve as critical quality filters in the patent system.

Two stages, one set of grounds 🔗

India offers opposition at two distinct stages of a patent’s life. Pre-grant opposition under Section 25(1) can be filed by any person after a patent application is published but before the patent is actually granted. Post-grant opposition under Section 25(2) is available to any interested person within 12 months of the publication of the grant. An “interested person” includes individuals or entities engaged in research or having a manufacturing, trading, or financial interest in the subject area – a deliberately broader category than it might initially appear.

What makes India’s system notable is that the grounds for both pre- and post-grant opposition are identical, listed exhaustively under clauses (a) to (k) of Section 25. No grounds outside this list can be introduced. This keeps the opposition process predictable and legally disciplined. Let’s go through these grounds in detail.

Wrongful obtainment 🔗

The first ground under Section 25(1)(a) targets situations where the applicant did not legitimately develop the invention – they obtained it, wholly or in part, from the opponent or someone else without authorization. This protects the true inventor’s rights and prevents intellectual theft from being laundered through a patent application. If a researcher shares an idea with a colleague in confidence and that colleague files a patent on it, wrongful obtainment would be the appropriate ground to oppose. The burden is on the opponent to demonstrate that the applicant had no rightful claim to the invention.

Anticipation by prior publication 🔗

Under Section 25(1)(b), a patent can be opposed if the invention was already disclosed in any published document – a journal article, a conference paper, a prior patent specification, or even a publicly available technical report – before the priority date of the applicant’s claim. This ground directly tests the novelty of the claimed invention. If the invention was already in the public domain through written material anywhere in the world, it cannot be validly patented.

This was one of the grounds successfully argued in the well-known Novartis vs. Cipla (2011) case, where Cipla opposed Novartis’s patent application for dispersible tablets. The Controller found that the claims were hit by prior publication, among other grounds, and refused the grant.

Prior claiming 🔗

Section 25(1)(c) applies where the claimed invention is already covered by another patent application filed in India with an earlier priority date, even if that application had not yet been published at the time of filing. This prevents overlapping patent claims over the same invention. It is a nuanced but important ground – it addresses the possibility of two separate applicants making substantially the same claim, and ensures the earlier filer is protected.

Publicly known or publicly used in India 🔗

Under Section 25(1)(d), an invention that was publicly known or used in India before the priority date of the applicant’s claim cannot be patented. This ground is particularly significant because it captures informal or unrecorded prior art – an invention that was in common use in a particular industry or locality, even if never published. Importantly, the Patents Act clarifies that if a product made by a process was already imported into India before the priority date (other than for trial purposes), the process is deemed to have been publicly known.

Obviousness and lack of inventive step 🔗

This is perhaps the most frequently invoked ground in patent opposition cases. Section 25(1)(e) allows opposition where the invention is obvious and clearly does not involve any inventive step when compared to the prior art. An “inventive step” under Section 2(1)(ja) of the Patents Act means a feature that makes the invention not obvious to a person skilled in the related field.

In practice, this ground challenges whether the inventor actually made a meaningful intellectual leap. If a skilled professional in the field would have arrived at the same invention by routine experimentation or by simply combining existing knowledge, the invention fails the inventive step test. In the post-grant opposition involving Natco Pharma vs. Novartis over the drug Ceritinib, the Controller revoked the patent precisely because the compound was found obvious in view of existing prior art – the Delhi High Court subsequently allowed Natco to manufacture a generic version.

Non-patentable subject matter 🔗

Section 25(1)(f) permits opposition when the claimed invention falls within the categories excluded from patentability under the Act – most notably under Section 3, which lists a broad range of non-patentable subject matter. This includes discoveries of natural phenomena, mathematical methods, business methods, computer programs per se, methods of treatment, and – critically for the pharmaceutical sector – substances that are merely new forms of a known substance without any significant increase in efficacy (Section 3(d)). In the Novartis vs. Cipla case, this ground was also raised, with Cipla arguing that the claimed substance had only additive properties expected from a mere admixture and was therefore excluded under Section 3(e).

Insufficient disclosure 🔗

Under Section 25(1)(g), an opposition can be filed on the ground that the complete specification does not sufficiently and clearly describe the invention or the method by which it is to be performed. Patent law requires that the specification enable a person skilled in the relevant field to reproduce the invention. If the disclosure is vague, incomplete, or misleading, the patent serves no public benefit – the whole premise of the patent bargain (monopoly rights in exchange for public disclosure) breaks down. This ground was raised in Hindustan Lever Ltd. v. Godrej Soaps (1996), where insufficiency of description was among the objections filed by Godrej. The Controller ultimately directed amendments to the specification before allowing the patent.

Failure to disclose foreign filings under Section 8 🔗

Section 25(1)(h) addresses a compliance obligation unique to Indian patent law. Under Section 8 of the Patents Act, an applicant who has filed or intends to file a patent application for the same invention in another country must disclose this information to the Indian Patent Office and keep it updated. Failure to comply – or furnishing false information – is a valid ground of opposition. This provision exists to allow the Indian Patent Office to take note of prior art and prosecution history in other jurisdictions, ensuring the Indian examination process is well-informed and not conducted in isolation.

Non-compliance with convention application timeline 🔗

Section 25(1)(i) applies specifically to convention applications – those filed in India claiming priority from an application in a Paris Convention member country. The law requires that the Indian application be filed within 12 months of the first filing in the convention country. If this deadline is missed, the applicant loses the right to claim that priority date, and this becomes a valid ground for opposition. This ground is procedural in nature but carries real substantive consequences, as missing the priority date can expose the application to prior art that emerged in the intervening period.

Non-disclosure of geographical origin of biological material 🔗

Under Section 25(1)(j), an invention that uses biological material must properly disclose the source and geographical origin of that material. If the applicant fails to disclose this, or makes a wrongful disclosure, the patent can be opposed. This ground has strong connections to India’s commitments under the Convention on Biological Diversity and the Nagoya Protocol on access and benefit sharing. It is particularly relevant to inventions in biotechnology, pharmaceuticals derived from natural compounds, and agricultural innovations that draw on biological resources.

Anticipation by traditional knowledge 🔗

Section 25(1)(k) is a ground that reflects India’s specific policy concern about biopiracy – the patenting of inventions that are actually rooted in the traditional knowledge of local or indigenous communities in India or elsewhere. If an invention is merely an application or adaptation of traditional knowledge, it can be opposed on this ground. India has proactively developed the Traditional Knowledge Digital Library (TKDL) – a searchable database of traditional medicinal formulations in multiple languages – precisely to provide examiners and opponents with documented prior art to challenge such claims. Several European and international patent applications have been successfully challenged using TKDL data.

Why these grounds matter as a system 🔗

Taken together, these grounds function as an interlocking framework. Some – like wrongful obtainment and failure to disclose Section 8 information – target procedural integrity. Others – like prior publication, public use, obviousness, and traditional knowledge – directly test whether the invention deserves a patent on its merits. And grounds like non-patentable subject matter and insufficient disclosure enforce the substantive standards that define what a patent can legitimately protect.

Importantly, if a granted patent survives a post-grant opposition, it emerges with considerably stronger legal standing – having been tested and validated not just by the Patent Office during examination, but also by an adversarial challenge. Conversely, when an opposition succeeds, it corrects a systemic error before it calcifies into a monopoly right that burdens public access or competitors in the market.

The pharmaceutical sector in India has historically been the arena where these grounds have been tested most vigorously – and the outcomes have had far-reaching consequences for drug pricing and access. But the principles apply equally to any technology domain.

What do you think? Given that both pre-grant and post-grant opposition share the same grounds, does it make sense to maintain two separate tracks – or would a single, more comprehensive opposition window serve the public interest better? And considering how the traditional knowledge ground has been used to fight biopiracy, do you think India’s current legal mechanisms are sufficient to prevent the misappropriation of indigenous knowledge through patents?

References

1. https://ipindia.gov.in/writereaddata/Portal/ev/sections/ps25.html
2. https://blog.ipleaders.in/patent-pre-grant-post-grant-opposition-procedure-india-vs-re-examination-us/
3. https://www.cbd.int/abs/
4. https://www.tkdl.res.in/
5. https://www.lexology.com/library/detail.aspx?g=a401f6dc-da48-4244-90c2-bada4a81b533