It is increasingly common for Indian patent applications to be met with objections or oppositions that the disclosure is not enough. R&D teams hear that “the specification does not enable a skilled person,” or that “the best method is missing,” and a grant suddenly feels distant. The worry is understandable. Indian law expects a fair bargain, a time-limited monopoly in exchange for a full teaching of the invention. When that teaching is questioned, what exactly happens, and what can you do?
The legal idea behind “sufficiency” in India
Indian law sets the bar in two places. First, every complete specification must fully and particularly describe the invention, its operation or use, and the method of performing it, and it must disclose the best method known to the applicant. These are hard statutory duties under Section 10(4).
Second, insufficiency is a ground to attack a patent at multiple stages. It can be raised in pre-grant opposition, post-grant opposition, and as a revocation ground. Section 25 permits opponents to rely on “insufficient or unclear description of the invention or the method,” and Section 64 allows revocation where the specification does not sufficiently and fairly describe the invention, including failure to disclose the best method.
In practice, Controllers and courts ask a simple question with a technical flavour. Could a person skilled in the art, using only the specification and common general knowledge, practise the invention without undue experimentation? If the answer is no, the disclosure is likely insufficient. Indian commentary and decisions consistently express the test in these terms.
Where and how the challenge lands
1) During examination
Insufficiency frequently appears in a First Examination Report as an objection under Section 10(4). If raised, the Controller must spell out what exactly is missing so the applicant can respond. Delhi High Court has stressed that vague, non-specific insufficiency objections are not acceptable.
2) Pre-grant opposition
Any person may file a pre-grant opposition after publication and before grant, using Form 7A with a statement of case and evidence. The procedure is in Rule 55 of the Patent Rules. By amendment in 2024, the Controller is obliged to issue a reasoned prima facie order on the representation, which has made pre-grant practice more structured. Insufficiency is a standard ground raised at this stage.
3) Post-grant opposition and revocation
Within one year of the publication of the grant, a “person interested” can file a post-grant opposition, which is handled by an Opposition Board constituted under Rule 56. Beyond that window, an interested person may seek revocation in court on grounds under Section 64, including insufficiency of disclosure and claims lacking clear definition.
What examiners and courts typically look for
From the files and reported orders, five themes recur.
Enablement, not perfection. The law requires a teaching that enables, not an exhaustive manual. But if core steps, parameters, or essential reagents are missing, enablement fails.
Best method is mandatory. The applicant must disclose the best method known at filing. Non-disclosure of best method can be fatal at revocation.
Working examples help, prophetic examples may not save you. Courts have cautioned that claims spanning broad families without concrete examples or specific teaching for key variants can run into Section 10(4) problems. Recent Delhi decisions in life sciences reiterate this.
Claim clarity overlaps with sufficiency. If claims are not sufficiently and clearly defined, Section 64(1)(i) presents an additional vulnerability, separate from enablement.
Consistency across the document. If examples contradict the general teaching, or critical ranges appear only in drawings or external references, the disclosure can be read as insufficient.
If you are hit with an insufficiency challenge, what happens next?
A challenge does not automatically kill the case. The process is structured, and there is room to fix genuine drafting gaps without overreaching.
You will be asked to answer on the record. In examination or pre-grant, you file a detailed response with technical explanations and, where appropriate, affidavits from domain experts. The Controller’s order must address your points.
Targeted amendments are possible, but adding matter is not. Sections 57 and 59 allow amendments by way of disclaimer, correction, or explanation, so long as you do not introduce new subject matter and do not enlarge claim scope. Use this carefully to clarify steps, define parameters, or align claims with the description.
Procedural safeguards apply. If a pre-grant representation is filed, grant will not occur before six months from publication, and the amended Rule 55 framework requires a reasoned prima facie decision, hearing if requested, and speaking orders.
Three focused questions founders ask
Do I really have to disclose the “best method”?
Yes. Section 10(4)(b) requires disclosure of the best method known at filing, and Section 64(1)(h) makes failure to do so a revocation ground. It is not an optional narrative, it is part of the legal bargain. In practice, the best method is the recipe your team would follow in the lab or on the line if asked to reproduce the invention today.
Are working examples compulsory to survive an attack?
There is no magic number of examples in the Act. However, where the claim covers a broad genus, Indian decisions increasingly expect examples or specific guidance for the key embodiments that matter. In biotech and chemistry, decisions have faulted applications that claim large classes without teaching insertions or substitutions with enough specificity. Provide at least one enabling route to practise the invention, and ensure the teaching maps onto the breadth of your claims.
Can I submit new experimental data to cure insufficiency?
You can explain, disclaim, or correct under Section 59. You cannot add matter that was not in substance disclosed on the filing date. Supplementary data may support what was already taught, for example to clarify ranges or show that stated steps indeed work, but it cannot backfill a missing core step or introduce a new feature. Controllers and courts read Section 59 strictly.
Practical playbook to defend against insufficiency
Before and at filing, write like a future opponent is reading
Identify the essential features, then describe them in operational terms.
Include the best method known, with specific reagents, apparatus, ranges, and conditions where relevant.
For broad claims, add examples across the breadth, not only at the centre. If the claim covers families, show at least one member of each meaningful subgroup.
During prosecution, close the gaps without crossing Section 59
Use amendments by explanation or disclaimer to align claim language with what the description already supports. File Form 13 where required, and keep your changes within the four corners of the original disclosure.
If the FER raises insufficiency, insist on specificity. Respond point by point and, where helpful, add expert declarations that explain why a person skilled in the art can perform the invention without undue experimentation.
In opposition or litigation, organise the record around the skilled person
Frame your evidence around what the skilled person would understand on the filing date. Show how common general knowledge plugs ordinary gaps. Courts repeatedly use this lens.
If the challenge alleges absence of best method, show where the specification teaches the most effective route you knew at filing. If not, consider whether a narrowing disclaimer keeps you within Section 59.
A simple self-audit for sufficiency
Can a skilled person run this without guesswork? If steps, ranges, or materials would need trial-and-error beyond routine, add detail.
Does the teaching match the breadth? If claims span categories, do examples or explicit guidance cover those categories.
Is the best method actually in the text? Check that the route your team prefers is disclosed, not just an alternative.
Are critical terms defined? Words like “about,” “substantially,” or “optimized” should have context or measurable boundaries.
Are drawings and sequences doing hidden work? Do not rely on external sources or unexplained figures for core steps.
A note on recent trends
Two developments are worth watching. First, the 2024 amendments to Rule 55 have tightened pre-grant practice, with reasoned prima facie orders and clearer hearing pathways. Second, recent Delhi High Court orders, especially in life sciences, have emphasised concrete, enabling disclosures for key variants rather than broad statements of result. Together, these trends reward well-crafted specifications and disciplined amendments.
When challenged for insufficient disclosure, the outcome often turns less on rhetoric and more on drafting discipline. The strongest defence is built on the day you file, with a specification that enables the invention across the claim breadth and honestly teaches the best method you know. If a challenge arrives, answer it with precision, use Section 59 sparingly to clarify without adding matter, and keep the skilled person at the centre of your narrative.
