The Spatial Effects and Mechanisms of Environmental Decentralization on Energy Eco-Efficiency in China: Evidence from a Quasi-Natural Experiment of the Carbon Emissions Trading Pilot Policy

This study employs a balanced panel dataset covering 257 prefecture-level cities in China from 2007 to 2020, integrating multidimensional indicators on the economy, energy, and environment. Energy ecological efficiency is measured using the Super-SBM model with undesirable outputs, taking into account both economic outputs and environmental emissions. Environmental decentralization is assessed through a comprehensive indicator system encompassing pollution control, resource utilization, and environmental law enforcement, with weights determined by the entropy method. Based on the implementation timeline and the list of pilot cities for China’s carbon emissions trading scheme, the sample is divided into treatment and control groups. A difference-in-differences (DID) model incorporating an interaction term between environmental decentralization and the policy is then constructed to identify the causal effect of environmental decentralization on energy ecological efficiency under the policy context. To address unobserved individual heterogeneity, a fixed-effects model is employed, and a mediation model is further used to explore the underlying mechanisms. The data are primarily sourced from the <i>China City Statistical Yearbook</i>, the <i>China Environmental Statistical Yearbook</i>, provincial and municipal statistical yearbooks, and publicly released statistics from relevant government departments, ensuring consistency and comparability across years.