<p>Understanding how the environment matters in developing, transmitting and spreading antimicrobial resistance (AMR) has become an important concern over the last decade. One concern is how waste from pharmaceutical manufacturing pollutes environments with effluents that contain antibiotics, potentially driving the growth of AMR. There has been a particular interest to address this at pharmaceutical production sites in India, due to the country’s status as one of the world’s largest producers of antibiotics. In this paper, based on document analysis and ethnographic fieldwork, I analyse science-policy responses to pharma-industrial antibiotic effluents and AMR in the environment in India. Paying particular attention to knowledge claims and contestations made by scientists and pharmaceutical industry actors, I demonstrate how various uncertainties emerge due to molecularised understandings of the environment and an emphasis on tracing cause–effect relations at the molecular scale. Contributing to the literature on molecularisation, I further show how the ontological multiplicity of antibiotics adds to the challenge of regulating pollution. Highlighting how antibiotics are situated in uneven geographies of pharmaceutical production and trade, I argue for the need to rethink current molecularised approaches and find alternative ways to approach the problem of industrial pollution and AMR in the environment.</p>