Recognizing that no central authority can combat climate change, scholars have pointed to the potential of polycentric governance in tackling climate change. Yet, empirical evidence for such a claim is scarce, particularly in the Global South. This study analyzes the characteristics, promises, and pitfalls of polycentric governance to promote climate mitigation efforts in three Indian states. Our contribution is twofold: (1) conceptually, we propose a framework to investigate the promises and pitfalls of polycentric climate governance in a federalist system with a particular focus on aspects of scaling and institutionalization, and (2) empirically, we compare solar power development across three Indian states with favorable conditions for solar power but varying performance. Based on a qualitative analysis of interviews and documents, we show how state governments with different party backgrounds have been vital in implementing policy changes and overcoming political barriers. Still, very few bottom-up initiatives exist and were successfully institutionalized.