Do energy-environmental efficiency benefit from advanced policy zones? Evidence from national new zones of China

As global climate change aggravates, reducing energy consumption and environmental pollution is essential to sustainable economic development. This paper measures the energy-environmental efficiency of 284 prefecture-level cities in China using a non-radial directional distance function (NDDF) and data envelopment analysis (DEA), and evaluates the impact of the establishment of national new zones on energy-environmental efficiency using the multi-period difference-in-difference model (DID). The results are: first, establishing national new zones improves the energy-environmental efficiency of the prefecture-level cities in which they are located by 13%-25%, and the mechanisms include enhancing the green technical efficiency and scale efficiency. Second, national new zones have both negative and positive spatial spillover effects. Third, in terms of heterogeneity, the impact of establishing national new zones on energy-environmental efficiency increases with larger quantile of the latter; national new zones with the one-city layout have significant stimulating impacts on energy-environmental efficiency, but those with the two-city layout have no significant impact, which means there is no significant green synergistic development impact among cities. We also discuss the policy implications of the research, including enhanced policy support and regulation to support the energy environment sector.