River basin management (RBM) as an approach to sustainable water use has become the dominant model of water policy. However, its implementation requires fundamental adjustments and rescaling of institutions in the water sector along hydrological boundaries. The creation of such a new level or scale of governance is in itself a political process, described in academic discussion as the "politics of scale."

The article examines how these "politics of scale" play out in the context of the institutionalization of RBM in Mongolia. Furthermore, it analyzes the role of comprehensive political decentralization processes on the implementation of RBM, a topic that has received little attention so far. Ultimately, this will allow us to assess whether the river basin is an appropriate scale for water governance in Mongolia.