Identifying the superposition effect of clean air policy and new energy demonstration city pilot policy on energy transition in China

Against the backdrop of intensifying climate change and air pollution, Clean Air Policy (CAP) and the New Energy Demonstration City (NEDC) pilot policy serve as foundational pillars of China's strategy to realize energy transition (ET). While the individual effects of each policy have been extensively studied, their potential superposition effect on ET remains unexplored. To investigate this superposition effect, we employ panel data covering 278 Chinese cities from 2010 to 2021. Our baseline regression results demonstrate a positive superposition effect of the two policies in promoting ET. The findings remains robust after a series of robustness tests. Mechanism analysis reveals that energy consumption reduction, industrial structure upgrading, and energy efficiency improvement are three transmission channels. Moreover, we find that the superposition of the two policies on ET exhibits heterogeneity across regions, urban scales, levels of economic development, resource endowments, environmental regulation intensity, and officials' promotion pressure, highlighting how local conditions shape policy effectiveness. These findings shed new light on the logical nexus among policy design, impact, and mechanism in this field, offering both theoretical insights and policy guidance for economies striving to achieve similar multi-dimensional goals.