Summary
The Delhi High Court upheld the rejection of Crystal Crop’s patent application for a herbicidal composition combining halosulfuron-methyl and metribuzin. The Court found that tweaking known ingredients is not innovation unless the applicant can show a real technical advance or a credible synergistic effect.
In Crystal Crop Protection Ltd vs Assistant Controller of Patents and Designs & Ors., the Delhi High Court dismissed an appeal challenging the rejection of Indian Patent Application No. 2228/DEL/2011 relating to a herbicidal composition. The application had been refused during pre-grant opposition proceedings on the grounds that the claimed composition lacked an inventive step and amounted to a mere admixture of known substances. The Court found no infirmity in the impugned order and held that the invention failed to demonstrate any technical advancement or synergistic effect necessary to qualify for patent protection.
Background
Crystal Crop Protection Ltd. (“Crystal Crop”) filed Indian Patent Application No. 2228/DEL/2011 titled “Herbicidal Composition for Field Crops” on 5 August 2011. The application claimed a herbicidal formulation consisting of specific proportions of halosulfuron-methyl and metribuzin for controlling weeds in field crops. The application faced two pre-grant oppositions under Section 25(1) of the Patents Act, 1970. The first opposition was filed in 2017 by the Haryana Pesticides Manufacturers’ Association (“Opponent 1”), followed by a second opposition in 2022 by Dr. Meera Sharma (“Opponent 2”). Hearings on both oppositions were conducted in February 2023, after which the parties submitted their written arguments.
By an order dated 28 March 2023, the Assistant Controller of Patents and Designs (“Controller”) rejected the application, holding that the claimed composition lacked an inventive step under Section 2(1)(ja) and was not patentable under Section 3(e), as it amounted to a mere admixture of known substances. Aggrieved by this decision, Crystal Crop filed an appeal before the Delhi High Court under Section 117A of the Patents Act.
During the appellate proceedings, Opponent 2 filed an application under the Delhi High Court Intellectual Property Division Rules, 2022 read with Order XLI Rule 27 and Section 151 of the Code of Civil Procedure seeking permission to place additional documents on record. These included regulatory registrations of certain herbicides with the United States Environmental Protection Agency, as well as scientific and academic materials to assist the Court in assessing the patentability of the invention.
Arguments by the Parties
Crystal Crop argued that the application to introduce additional documents should be rejected, as it did not meet the requirements of Order XLI Rule 27 of the Code of Civil Procedure. They contended that the documents were publicly available and could have been presented before the Controller during the pre-grant opposition proceedings. Allowing them at the appellate stage, they argued, would unfairly permit the opponents to fill gaps in their case and introduce new evidence that had not been considered earlier. Crystal Crop further maintained that the invention involved a synergistic herbicidal composition of halosulfuron-methyl and metribuzin in specific proportions that produced an effect greater than the additive effect of the individual components. They relied on experimental data in the specification to demonstrate that the composition achieved improved weed control at lower dosages and hence satisfied the requirements of patentability under Section 3(e) of the Patents Act.
The opponents contended that the claimed invention failed to demonstrate an inventive step. They asserted that prior art already disclosed the use of halosulfuron-methyl and metribuzin in herbicidal formulations, and that applicant had merely altered the proportions of known ingredients without any real technical advancement or proven synergistic effect.
The Controller defended the rejection of the patent application and maintained that the composition was obvious in light of existing prior art and amounted to a mere admixture of known substances under Section 3(e).
Observations by the Court
The Court observed that appellate courts may permit additional evidence when it is necessary for the proper adjudication of the case. It noted that the grant of a patent confers a monopoly that affects the public at large and hence patents should be granted only when all statutory requirements are met. The Court allowed the additional prior-art documents to be taken on record and considered them in evaluating the patentability of the invention.
The Court further compared the claimed composition with the cited prior art and noted that some references already disclosed compositions containing halosulfuron-methyl and metribuzin in proportions comparable to those claimed. It observed that merely adjusting the proportions of known components does not, by itself, establish an inventive step unless it produces a demonstrable technical advancement.
The Court reiterated that when a patent claim involves a combination of known substances, the applicant must demonstrate that the combination yields a synergistic result that goes exceeding the additive effect of the individual components. The Court found that the experimental data placed on record did not convincingly establish such synergy. Instead, the increased efficacy observed in the experiments appeared to result from higher overall dosages of the active ingredients rather than from any unexpected technical effect attributable to the specific ratio claimed in the invention.
Conclusion
The Court held that the Controller had correctly assessed the patent application and found that the claimed herbicidal composition lacked an inventive step and did not demonstrate a synergistic effect. Accordingly, the appeal was dismissed and the refusal of the patent application was upheld.
Citation: Crystal Crop Protection Ltd vs Assistant Controller of Patents and Designs & Ors., 28 February, 2026, Delhi High Court, C.A.(COMM.IPD-PAT) 19/2023 & I.A. 20715/2025
Available at: https://indiankanoon.org/doc/64918310/
Article Review: Dr. Vasundhara Paliwal