Hindsight is the permanent occupational hazard of assessing inventive step. Once an invention has been explained, it tends to look inevitable. The components were all known. The problem was well understood. Somebody was going to put them together.

The legal tests for obviousness exist to discipline that instinct — to force the assessor back to the position of the skilled person before the invention, working with the prior art as it actually stood. Applying those tests is laborious, and the temptation to skip to the conclusion is considerable.

The Delhi High Court has set aside a revocation order for doing precisely that.

An Unglamorous Invention

The patent covered a process for producing hard carbon electrode material from cattle manure, for use in sodium ion batteries and supercapacitors. It was filed on 4 November 2020 and granted on 4 August 2021.

It is worth pausing on what this is. Sodium ion batteries are one of the more credible routes around lithium dependence, and hard carbon is a standard anode material for them — ordinarily produced from biomass or petroleum-derived precursors. Deriving it from cattle manure addresses two problems at once: a waste stream India has in enormous quantity, and a battery input it would rather not import.

This is exactly the kind of applied, resource-specific invention that Indian research institutions produce and that the patent system is supposed to reward.

Revoked in Post-Grant Opposition

A post-grant opposition was filed challenging the patent on lack of novelty, lack of inventive step, and insufficiency of disclosure.

On 18 October 2024 the Patent Office revoked it. The novelty objection was rejected — the invention was found to be new. But the Deputy Controller upheld the objections on inventive step and insufficient disclosure, and the patent went.

The patentee appealed.

What the Court Found Missing

The High Court set aside the revocation and sent the matter back for fresh consideration, with a direction to decide within four months.

The ground was not that the invention was inventive. The Court did not decide that, and was careful not to. The ground was that the Deputy Controller had failed to properly apply the established legal test for assessing inventive step.

That distinction is the whole of the judgment's value. Indian law has a settled structure for obviousness — identify the person skilled in the art and their common general knowledge, identify the closest prior art, identify the difference between that art and the claimed invention, and then ask whether that difference would have been obvious to the skilled person without the benefit of hindsight. It is a sequence, and the sequence is the safeguard.

An order that announces the conclusion without visibly working through the steps cannot be reviewed, because there is nothing to review. The appellate court cannot tell whether the right prior art was used, whether the skilled person was correctly characterised, or whether hindsight crept in. Remand is the only available response.

The Pattern This Belongs To

This is not an isolated correction. The Delhi High Court's patent bench has been returning refusals and revocations to the Patent Office with increasing regularity, and the reasons rhyme: conclusions stated rather than reasoned, statutory tests recited rather than applied, objections under section 3(d) or on obviousness disposed of in a paragraph that does not engage with the applicant's response.

The Court has been explicit that a mechanical approach will not survive scrutiny, and that patentability findings require a thoughtful application of mind.

There is a real cost attached to that pattern, and it is not borne by the Patent Office. This patent was granted in August 2021, revoked in October 2024, and as of the remand is back where it was — with four more months allotted for a decision that should have been made properly the first time. Five years of a twenty-year term have gone, and the patentee still does not know whether it holds anything.

The Takeaway

For patentees facing revocation or refusal, the appealable defect is often procedural rather than substantive. An order that does not show its reasoning on inventive step is vulnerable regardless of whether the underlying conclusion was defensible — and identifying that gap is frequently a stronger appeal than arguing the merits of obviousness afresh. Reading the order for what it fails to do is the first task, not the last.

For opponents in post-grant proceedings, the corollary. A revocation obtained on a thin order is not a durable win. Building the obviousness case through the full structure — with the closest prior art properly identified and the skilled person's knowledge established on evidence — is what produces a finding that survives section 117A.

And for anyone weighing whether an Indian patent is worth pursuing in a research-heavy, applied field: the appellate route works, but it is measured in years. The examination stage is where a case is actually won, and the quality of the response to the first examination report matters more than any later argument.