The India-EU Ideathon on “Combating Marine Plastic Litter” was officially launched on 25 September 2025. Organised by the Office of the Principal Scientific Adviser (OPSA) to the Government of India in partnership with the Delegation of the European Union (EU) to India, the initiative falls under the India-EU Trade and Technology Council (TTC) Working Group 2 on Green and Clean Energy Technologies. The Ideathon invites start-ups, researchers, businesses, and other stakeholders from India and the EU to co-develop innovative solutions to tackle marine plastic pollution.Dr Parvinder Maini, Scientific Secretary, OPSA, and Ms Signe Ratso, Deputy Director-General for Research and Innovation at the European Commission, co-chaired the event. Dr Maini emphasised that the Ideathon represents a collaborative effort to develop solutions that are globally relevant yet locally effective, citing India’s Swachh Sagar, Surakshit Sagar campaign and the nationwide ban on single-use plastics. Ms Ratso highlighted the importance of EU-India cooperation in addressing marine plastic pollution, which threatens marine life, public health, and coastal economies.The event featured presentations on the landscape of marine plastic litter by Prof Hoysala N. Chanakya, Indian Institute of Science, Bangalore, and Mr John Hanus, European Commission, highlighting challenges and ongoing research in both regions.Three core challenges were identified for participants:1. Tracking marine plastics to develop innovative monitoring approaches.2. Developing scalable technologies for removing marine plastics.3. Raising awareness and mobilising communities to prevent plastic pollution.Over 750 participants joined from India and the EU, including government officials, researchers, start-ups, businesses, and civil society organisations. Experts such as Prof E.V. Ramasamy, Dr Pravakar Mishra, Dr Ajay Karmarkar, Dr K Ramu, Dr S.R. Marigoudar, Dr Robin R.S, Ms Pilar Zorzo Gallego, Dr Vanessa-Sarah Salvo, and Dr Vesna Kuralt contributed insights during the event.