By Lucy Rana, Renu Bala & Aastha Suri
A process patent protects a way of making a product, but the making happens behind a competitor’s factory gates, where the patentee cannot see. Indian law answers that problem by providing for a possible shift in the burden of proof in specified circumstances. In NOCIL v. Finorchem, the High Court at Calcutta applied that shift, and a cluster of related doctrines, to grant a rubber chemicals maker interim protection for its process patents.
| ANSWER IN BRIEF
In a process patent infringement suit, once the patentee shows that the rival’s product is identical to the product made by the patented process, Section 104A of the Patents Act, 1970 shifts the burden to the defendant to prove that its process is different. The Court held that the patentee need not first establish the ultimate validity of the patent before the burden shifts. However, product identity alone is not the entire statutory test: Section 104A also requires one of the conditions specified in subsection (1)(a) or (b). The High Court at Calcutta held that a would-be entrant who launches a process that may be covered by an existing patent must “clear the way” first, by opposition, revocation or a declaration of non-infringement, rather than waiting to be sued, and that a defendant must raise a credible challenge, not a fanciful one, to resist an injunction. The Court treated the absence of a prior patent challenge as a factor in its interim assessment. The “clear the way” principle should not be presented as an express, universal statutory obligation applicable to every prospective entrant. Applying the pith and marrow test, the Court found the defendant’s process prima facie equivalent to the patented process, found its shifting, inconsistent disclosures and its patent amendments to be an attempt to evade liability, and granted NOCIL an interim injunction. These are prima facie findings in an interim order; the suit continues to trial. |
Enforcing a process patent is among the hardest tasks in patent litigation, because the alleged infringement is concealed inside the defendant’s manufacturing operations. A patentee can see that a rival is selling the same product, but it cannot see how that product is made. Section 104A of the Patents Act, 1970 was enacted to meet that difficulty, and its working, alongside the doctrines of credible challenge, clearing the way and pith and marrow, is on clear display in the 7 October 2026 decision of the High Court at Calcutta in NOCIL Ltd v. Finorchem Ltd, an order of its Intellectual Property Rights Division that is instructive for patentees and would-be competitors across India.
Process patents and the problem of proof
The general rule is that the burden of establishing infringement rests on the patentee. For a process patent that rule is unworkable, because only the defendant knows the process it uses behind closed doors. Section 104A addresses this by reversing the burden in defined circumstances: where the subject matter is a process for obtaining a product, and the patentee proves that the defendant’s product is identical to the product obtained by the patented process, the court may require the defendant to prove that the process it uses is different from the patented process.
Product identity is a necessary condition, but Section 104A(1) also requires either that the patented process is for obtaining a new product, or that there is a substantial likelihood that the identical product was made by the patented process and the patentee was unable, despite reasonable efforts, to determine the process actually used. The court may then direct the defendant to prove that its process is different. While directing disclosure, the court is expected to protect the defendant’s genuine trade and commercial secrets.
Section 104A in action: the burden shifts
In NOCIL v. Finorchem the trigger was admitted. NOCIL Ltd, one of the largest manufacturers of rubber chemicals in India, had developed around 2012 a process for manufacturing 4-aminodiphenylamine, known as 4-ADPA, an antioxidant used in rubber and polymer applications, and held three Indian process patents for it, with equivalent patents granted in the United States. Finorchem Ltd proposed to manufacture the very same product, 4-ADPA.
Because the end products were admittedly identical, the Court held that the burden lay on Finorchem to prove that its process was different from the patented process, and rejected the argument that the patentee had first to establish the validity of its patents before that burden could shift. This was the Court’s conclusion on the facts before it. Section 104A’s additional statutory conditions must still be considered when applying the provision in other cases.
Finorchem, the Court found, failed to discharge the burden: it had given at least three different and inconsistent versions of its process, its environmental impact report was virtually identical to NOCIL’s, its claim to use a different catalyst was found to be false, and its later patent amendments, deleting a molar ratio and recasting an inventive second hydrogenation step as merely optional, were, in the Court’s words, nothing more than an attempt to evade liability for infringement. More precisely, these were proposed amendments to Finorchem’s patent application, and the Court treated them as evidence relevant to its prima facie assessment.
Clearing the way, and the credible challenge test
Two further doctrines shaped the outcome. First, the Court applied the clear the way principle: a new entrant that wishes to launch a process which may be covered by an existing patent must take steps to remove the obstacle before it starts, by filing a pre-grant or post-grant opposition, a revocation application under Section 64, or a suit for a declaration of non-infringement under Section 105, rather than simply launching and waiting to be sued.
Finorchem had done none of these before the suit, which weighed against it. This reflects the Court’s reasoning in this case. The principle is a judicial consideration in assessing the circumstances of patent litigation and interim relief; it should not be stated as an absolute statutory requirement that every prospective entrant must challenge a potentially relevant patent before commencing activities.
Second, on validity, the Court confirmed that while the grant of a patent is not, by itself, proof of its validity, unlike a trade mark registration, a defendant resisting an injunction must raise a credible challenge, one that is prima facie acceptable and not fanciful, illusory or moonshine. The onus of raising such a challenge lies on the defendant, and Finorchem had not discharged it, the more so because NOCIL’s patents were old, established and worked, had survived examination in India, the United States and Europe, and had been commercially exploited without interruption for over a decade.
The Court considered the history of examination and exploitation as part of its interim assessment. These circumstances do not conclusively establish patent validity, which remains open to determination in accordance with the Act and the evidence.
Pith and marrow, and the comparison of processes
On infringement itself, the Court applied the pith and marrow test. The question is not whether every detail of the defendant’s process matches the specification, but whether the essential, inventive features of the patented process have been taken; unessential features and trifling variations are ignored. Comparing NOCIL’s patent claims with Finorchem’s process, the Court found a series of common steps and held the two processes to be prima facie equivalent, with the differences Finorchem advanced being minor and inconsequential, and in part engineered to create an illusion of difference. The patentee’s expert evidence on this point was uncontroverted.
This was the Court’s prima facie comparison of the claimed process and the process disclosed by Finorchem. The test should not be understood as permitting courts to disregard the patent claims or technically material differences; the assessment must be grounded in the claims and the applicable principles of infringement.
Trade secrets and the ex-employee’s NDA
The case had a second limb, on confidentiality. The second defendant was a long-serving NOCIL employee who had worked on the development of the 4-ADPA process, had been posted as head of operations at NOCIL’s plant at Dahej in Gujarat, and had signed a non-disclosure agreement in 2012 that referred specifically to 4-ADPA. After his retirement he was engaged by Finorchem.
The Court held, prima facie, that he had been privy to NOCIL’s confidential information and trade secrets, that the NDA bound him not to disclose them, and that Finorchem had procured the breach of that NDA. An employee or ex-employee, the Court observed, cannot take advantage of trade secrets developed by another and use them for his own gain, and the fact that some elements of the information might be in the public domain does not strip the whole of its confidential character. The Court also rejected the argument that a confidentiality claim and an infringement claim are mutually destructive.
The findings concern the specific evidence and contractual obligations in this case. Hiring a former employee who possesses technical knowledge does not, by itself, establish misappropriation or procurement of a breach; the relevant information, obligations and conduct must be proved.
The outcome
Weighing these threads together, the Court held that NOCIL had made out a strong prima facie case, that the balance of convenience lay in its favour, and that irreparable injury would follow if protection were refused, noting that Finorchem had not yet begun commercial production. It granted an interim injunction in NOCIL’s favour.
It is important to be precise about the stage: these are prima facie findings on an interim application, and the questions of infringement and validity are to be finally decided after the expert evidence is assessed at trial. The suit continues.
Why this matters
For businesses on either side of a process patent in India, the decision is a practical guide. For patentees, especially in chemicals, pharmaceuticals and manufacturing, it confirms that Section 104A is a potentially important evidentiary mechanism, provided product identity and the additional statutory conditions are established. Old, worked patents and clean, consistent conduct strengthen the case.
For would-be entrants and generic manufacturers, the message is equally clear: assess potentially relevant patents and consider appropriate challenge or declaratory proceedings where warranted before making substantial commercial commitments; raise a credible challenge, not a shot in the dark; and keep your disclosures consistent, because shifting accounts of your own process are read as evasion.
And for every business that relies on trade secrets, the case is a reminder that a well-drafted non-disclosure agreement with key technical staff is enforceable, and that a competitor who hires away a rival’s people to acquire its know-howmay face liability where the evidence establishes misuse of confidential information or procurement of a contractual breach.
Frequently asked questions
Patent Infringement Faqs
Ordinarily the patentee. But under Section 104A of the Patents Act, 1970, once the patentee proves that the defendant’s product is identical to the product made by the patented process, the burden shifts to the defendant to prove that its process is different.. Product identity is necessary, but one of the additional conditions in Section 104A(1)(a) or (b) must also be satisfied before the court may direct the defendant to prove that its process is different.
No. The High Court at Calcutta held in NOCIL v. Finorchem that the patentee need not first establish validity before the burden shifts under Section 104A; the shift follows once the products are shown to be identical. The statutory conditions governing the shift must nevertheless be met. The defendant may still raise a credible challenge to validity as a defence.
It is the principle that a business intending to launch a process that may be covered by an existing patent should remove the obstacle first, for example by a pre-grant or post-grant opposition, a revocation application, or a suit for a declaration of non-infringement, rather than launching and waiting to be sued. Failing to clear the way weighs against the entrant at the interim stage. The principle should not be treated as a universal statutory obligation applicable to every prospective entrant.
It is the test for infringement that looks at whether the essential, inventive features of the patented process have been taken, ignoring unessential features and trifling variations, rather than requiring an exact, detail-by-detail match. Its application remains dependent on the patent claims and the relevant technical evidence.
It can. The Court held, prima facie, that engaging a former employee bound by a non-disclosure agreement, in order to acquire a rival’s confidential process, can amount to procuring a breach of that agreement and misappropriation of trade secrets, which the court will restrain. Liability depends on evidence of the relevant contractual obligation, confidential information and misuse or disclosure; the act of hiring alone is insufficient.
NOCIL v. Finorchem is a compact illustration of how Indian law protects process innovation when the infringement is hidden from view. Section 104A may shift the burden when its statutory conditions are satisfied, the clear the way doctrine may be relevant to the court’s assessment of a prospective entrant’s conduct, the credible challenge test filters out hollow defences, the pith and marrow test looks past cosmetic differences, and the law of confidence guards the know-how behind the process. The decision illustrates how these doctrines may operate together at the interim stage, without replacing the need for final findings on infringement, validity and confidentiality.
Source: NOCIL Ltd v. Finorchem Ltd & Anr., IA No. GA-COM/1/2024 in IP-COM/25/2024, High Court at Calcutta, Intellectual Property Rights Division (Original Side), judgment dated 7 October 2026 (Ravi Krishan Kapur, J.). The order grants interim relief and its findings are prima facie; infringement and validity are to be decided at trial. The statutory framework is the Patents Act, 1970, including Sections 48, 64, 104A, 105 and 107.
Disclaimer: This article is published for general information and educational purposes only. It does not constitute legal advice and is not intended as an advertisement or solicitation of work. Readers should obtain specific professional advice before acting on any matter discussed here.
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