Moldtek Packaging Ltd. (Moldtek) is the proprietor of Indian patent numbers IN 401417 and IN 298724, covering tamper-proof plastic lids for food containers. Moldtek had filed a suit for patent infringement against Pronton Plast Pack Pvt. Ltd. (Pronton) before the Commercial Court and successfully secured an ex parte injunction.

However, Pronton challenged the credibility of the suit patents on the ground of novelty vis-à-vis prior art, and suppression of material facts by Moldtek, following which the commercial court vacated the ex parte injunction. Importantly, the commercial court placed the burden of proof for proving the validity of the patent on Moldtek and conducted a product-to-product comparison rather than mapping the allegedly infringing product against the patent claims.

On appeal, the Delhi High Court (Court) set aside the Commercial Court’s order and remanded the matter for reconsideration. The Delhi High Court held that the Commercial Court had not assessed the infringement appropriately. The Court held that infringement must be assessed by comparing the infringing product with the claims of the patents. Further, the Court held that the burden of proof to prove the invalidity of the patents lies with the defendant, i.e., Pronton. Interestingly, the Court pointed out that there is a gap in the Patents Act, which, unlike the Trademarks Act, Copyright Act, or Designs Act, does not define “infringement”. The Court advised legislative clarification in the statute to ensure precision and certainty in infringement determinations.

This judgement offers critical guidance for patent litigation in India by clarifying that: (i) infringement assessment must be claim-based, and (ii) defendants bear the onus of proving patent invalidity when such a defence is raised.