[Dura-Line India Pvt. Ltd. v. Jain Irrigation Systems Ltd.; 2025: DHC: 4036][1]
The Hon’ble High Court of Delhi pronounced its judgment on 19th May, 2025 in a decade old lis between Dura-Line India Pvt. Ltd. (‘Plaintiff’) and Jain Irrigation Systems Ltd. (‘Defendant’). The Hon’ble Court adjudicated on a crucial question as to whether the Plaintiff’s claimed invention constituted a genuine technical advance meriting patent protection, or whether it amounted to no more than a routine and obvious refinement of pre-existing knowledge.
Factual matrix of the dispute:
The Plaintiff is an international manufacturer and distributor of infrastructure systems, including conduit, cable-in-conduit assemblies, water pipes, and related accessories, catering to the sectors of communication, energy and water. Whereas, the Defendant is a manufacturer of plastic pipes in India. The Plaintiff’s patent pertained to a pipe with a co-extruded tracer cable positioned on its outer surface titled “A Pipe Assembly Having Traceability and Leakage Detection Features” (‘Plaintiff’s Patent’ / ‘Patent’). The Hon’ble Court observed that the novelty and inventive step of the Plaintiff’s Patent lies in the combination of the following elements of the Plaintiff’s pipe assembly:- a non-metallic pipe (10) for fluid transport;
- a co-extruded tracer cable (40) on said non-metallic pipe to which pulses may be applied to locate the said non-metallic pipe and for detecting leakage on the same;
- a polymer based co-extruded tracer cable.
- Proprietary rights of the Plaintiff in its Patent: To establish proprietary rights in its Patent, the Plaintiff had filed a certified copy of the Patent Certificate along with the complete specification evidencing that its Patent was registered on 30th August, 2007. The Hon’ble Court noted, once a patent is granted and registered in the name of an applicant, the burden of disproving proprietorship lies on the party asserting otherwise. Further, the Defendant did not adduce any evidence to dispute the Plaintiff’s proprietorship rights in its Patent. Accordingly, the Hon’ble Court held that in the absence of any challenge to the Plaintiff’s title over its Patent, or evidence to the contrary, thus there was no reason to question the Plaintiff’s proprietary rights in its Patent.
- Whether the grant of the Plaintiff’s Patent was valid
The Defendant had challenged the validity of the Plaintiff’s Patent under Sections 64(1)(e), (f), (h), and (i) of the Patent Act, 1970 (‘Act’). It was the Defendant’s case that the Plaintiff’s Patent lacked novelty, does not have an inventive step, suffers from insufficient description of invention & manner of performance and scope of claims did not clearly or sufficiently define the claims. The Hon’ble Court dealt with each and every ground of challenge raised by the Defendant against the Plaintiff’s Patent and held that the Plaintiff’s Patent was valid. The Defendant during the course of proceedings highlighted only five select pieces of prior art to rebut the presumption of validity of the Plaintiff’s Patent under Sections 13(4) and 64(1) of the Act, though in the written statement, reliance was placed on 20 prior art documents. The Defendant’s contentions and the Hon’ble Court’s decision on the same are elucidated below:
- Lack of Novelty under Section 64(1)(e) of the Act:Defendant’s Contentions: The Defendant claimed that the Plaintiff’s Patent lacked novelty since prior arts viz. Ex DW2/1, Ex DW2/2, Ex DW2/3, Ex DW2/4 and Ex DW2/10 disclose the features of the Patent, more specifically Ex DW2/3, which was an NHAI tender document. Decision of the Hon’ble Court: For revocation of a patent because of lack of novelty under Section 64(1)(e) of the Act, the test is whether one prior art discloses each element of the patented claim either explicitly or implicitly. In addition, the Hon’ble Court observed that it is a well-settled principle of law that obviousness must be by a clear and unambiguous disclosure and that mosaic reconstruction from multiple documents cannot undermine novelty. Thus, to prove lack of novelty, each and every element of the claimed invention must be disclosed in a single prior art document and “Mosaic reconstruction” from multiple documents cannot undermine novelty. On the touchstone of this test, the Hon’ble Court rejected the argument of the Defendant under Section 64(1)(e), since none of the cited documents viz. Ex DW2/1, Ex DW2/2, Ex DW2/3, Ex DW2/4 or Ex DW2/10, individually disclosed all features of the Plaintiff’s Patent in combination. For specifically Ex DW2/3, the Hon’ble Court observed that Ex DW2/3 does not describe how the tracer cable is co-extruded on the pipe and it also does not explain whether the wire is laid on the outer surface or embedded within; whether it is simultaneously extruded or manually inserted; or whether it is encased in polymeric material. The Hon’ble Court held that – “The absence of detail regarding the structural configuration and the manufacturing process, particularly co-extrusion, means that the NHAI tender cannot be said to disclose the invention in its entirety.”
- Invention is Obvious or lacks Inventive Step under Section 64(1)(f) of the Act:Defendant’s Contention(s): Prior arts cited by the Defendant demonstrate that they clearly teach, suggest and motivate a person skilled in the art (‘PSA’) to make a HDPE pipe, wherein the tracer wire is placed on the top and the tracer wire is made by co-extrusion. Co-extrusion is a known process, methods such as welding, extrusion and sticking were being used to place the tracer cable on the pipe. Therefore, the Defendant argued that the Plaintiff has merely substituted the said process with co-extrusion and thus the alleged invention was obvious to try. Decision of the Hon’ble Court: To ascertain whether the Plaintiff’s Patent has an inventive step or not, the Hon’ble Court applied a five-step framework that has been discussed by the Division bench in F. Hoffmann-La Roche Ltd. v. Cipla Ltd.[2] After applying the five-steps framework the Hon’ble Court held that the Plaintiff’s Patent was not based on a predictable and/or routine adaption. Since, there was no evidence to suggest that it was common general knowledge to integrate a tracer wire as a co-extruded structural feature on the outer surface of the pipe and encased in polymer material to serve both mechanical and locational functions. Further, the alleged prior arts, relied on by the Defendant, neither individually, nor in combination offered any direct or implicit motivation to place a tracer wire via co-extrusion on the outer surface of a fluid-transporting non-metallic pipe. Additionally, the Plaintiff’s Patent identified the limitations in existing solutions and proposed a streamlined alternative through surface co-extrusion. The statutory definition of Section 2(1)(ja) of the Act, which defines ‘inventive step’, permits either technical advance or economic significance. The specification of the Plaintiff’s Patent highlights simplification of installation, prevention of cable damage and avoidance of pipe-wall compromise, which are commercial and operational advantages that support inventive merit. On the argument of substitution of technique raised by the Defendant, the Hon’ble Court stated that the assertion that it was “obvious to try” fails, since mere substitution of techniques was not enough; there must be a reasonable expectation of success. Accordingly, the Defendant failed to establish that the Plaintiff’s Patent lacked an inventive step under Section 64(1)(f) of the Act. Pertinently, the Hon’ble Court consciously avoided hindsight bias, in judging obviousness argument and found that the Defendant’s approach, reflects an ex-post construction rather than a credible roadmap that PSA would have followed on priority date. The Hon’ble Court held that such retrospective rationalisation fails legal threshold for obviousness.
- Objections under Section 64(1)(h) and (i) of the Act:Defendant’s Contentions: The complete specification of the Plaintiff’s Patent failed to explain the process of co-extrusion with sufficient detail; as to how it is to be executed or what benefit it provides. Decision of the Hon’ble Court: There was an inconsistency in the Defendant’s approach, since, the Defendant sought to rely on Ex DW2/3 as prior art and disqualify it for lack of enabling disclosure and at the same time challenged the sufficiency of the Patent in question for not elaborating on co-extrusion. This dual approach undermined the credibility of the Defendant’s objection. The complete specification of the Plaintiff’s Patent clearly elaborates to a PSA to perform the invention without providing any undue burden. In other words, the Plaintiff’s specification, when looked as a whole, sets out – (a) invention’s essential features and (b) the working manner, which helps a PSA, who has common general knowledge of the field to implement the said invention effectively. Thus, the objections raised under Sections 64(1)(h) and 64(1)(i) of the Act, were devoid of merit.
- Whether Defendant’s Impugned Products infringed the Plaintiff’s Patent: Defendant’s Contentions: The Defendant contented that the methods used to manufacture the Impugned Products were freely accessible and available in the public domain for decades, particularly for locating subterranean fluid-transport pipelines. Thus, the methods used by the Defendant were neither novel nor proprietary, therefore, such methods would fall outside the purview of any patent monopoly as they are lawfully available for public use. Further, the Defendant stated that in cross-examination of DW-2, it became apparent that the Defendant uses a two-step process, i.e. first extruding the pipe, and only thereafter affixing the tracer cable to the surface, whereas, the Plaintiff’s Patent dealt with co-extrusion. Lastly, on the issue of infringement it was contended that the Plaintiff and Defendant’s products when juxtaposed with Ex DW2/10 appeared structurally distinguishable, which meant that the Plaintiff cannot allege infringement, when its product is covered by prior art. Decision of the Hon’ble Court: The Plaintiff’s claims were not merely supported by documentary evidence, but were substantiated through the Defendant’s own product manuals and admissions made during cross-examination. The argument of the Defendant that it employs a different process was of limited consequence, since the infringement jurisprudence is anchored in doctrine of substance over form, the inquiry is not into the method but whether the product, as it exists, embodies the essential features of the patented invention. Moreover, it is a settled principle of law that for ascertaining infringement of a patent, the infringing products are to be compared with claims of the patent and not with the patentee’s commercial embodiment. Accordingly, the Hon’ble Court held that where the final product results in the same configuration, the method of assembly becomes immaterial. Consequently, it is affirmed that the Defendant’s Impugned Products incorporate all the essential elements qua the Claim 1 of the Plaintiff’s Patent, thereby upholding that the Impugned Products infringed the Plaintiff’s Patent. On the issue of comparison with the Plaintiff’s Patent, Impugned Products, and Ex DW2/10, the Hon’ble Court reproduced the three products (refer Figure A, below) and observed that the line of reasoning of the Defendant conflates two distinct inquiries: infringement and invalidity. The assertion of parity is therefore illusory.
Figure A
In light of the above, the suit was decreed in favor of the Plaintiff, thereby granting them a decree of rendition of accounts and recovery of full commercial costs. The contention of the Defendant that Plaintiff should have laid an adequate foundation for seeking rendition of accounts was rejected on the ground that once infringement is established and Plaintiff has sought relief of accounts in the pleadings, the court must proceed to evaluate whether such relief is warranted. Additionally, the Hon’ble Court directed the Registry to issue a certificate of validity of the Plaintiff’s Patent in accordance with Section 113 of the Act. This judgment by the Hon’ble High Court of Delhi serves as a crucial precedent, particularly in patent disputes and litigation in India. It re-establishes and upholds the tests for impugning patent validity and deciding patent infringements including:- For establishing novelty, the test is that one prior art should disclose each element of the patented claim;
- To constitute prior art, a document must enable PSA to perform the invention without further ingenuity;
- Obviousness must be by a clear disclosure and mosaic reconstruction from multiple documents cannot undermine novelty;
- Section 2(1)(ja) permits either technical advance or economic significance and not both;
- Hindsight Bias should be avoided while deciding on obviousness;
- For the argument of obviousness to succeed, it should be shown that there is a reasoned motivation to pursue the route of invention;
- Requirement of sufficiency under Section 64(1)(h) of the Act, is satisfied when the disclosure made in the claims is sufficient to enable the whole width of the claimed invention to be performed;
- Patent infringement is assessed by comparing the infringing product with the claims, not with the patentee’s commercial embodiment; what matters is that the impugned product, viewed through lens of structure and function, appropriates the core inventive concept, i.e. the pith and marrow of the claim.