This project aims to contribute scholarly insights and policy recommendations to advance the roles of municipalities in urban river governance in the context of global pollution challenges. While local capacity is important for tackling global change problems, in practice, many sustainability challenges fail to gain traction due to limited local capacity for policy implementation. Our project explored this knowledge-practice gap by investigating governance dynamics at the municipal level that have shaped the implementation of a transboundary river policy. We focus on municipalities in the vulnerable upstream area of the Citarum River, Indonesia, one of the most heavily polluted in the world. The government has promoted an integrated water resource management approach, notably by enacting a Presidential Regulation in 2018 to accelerate the transboundary revitalization of the Citarum, although this has been met with implementation challenges at the local level.