ABSTRACTMumbai's dumping grounds, located on the city's estuarine edge, are sites where garbage and marsh are turned into salable land. This process of translating waste into land depends on keeping matter, beings, and landscapes separate and on limiting their interactions. Yet waste and the marsh interact and transform in ways that escape managerial discourse, revealing a haze of category and control errors that complicate knowledge, agency, and responsibility. While developers translate waste to land in relation to developmental goals, fishing communities, scientists, and activists translate it differently: scientists translate it in relation to chemical properties, interactions, and timelines; marine‐life activists draw attention to its coastal ecologies; and fisher communities look for productive possibilities on a polluted shore. These translations attend to the inseparability of waste substances from the coast and its futures. They articulate a politics that acknowledges waste's sociopolitics, material agency, temporalities, and multispecies ethics. [coast, waste, development, pollution, marine life, ecology, chemistry, Mumbai]