Whether the Establishment of Pilot Free Trade Zones Improves Urban Carbon Emission Efficiency: An Analysis Based on Difference-in-Difference Model

Pilot free trade zones are the key to achieving green and sustainable economic development and promoting high-level protection of the ecological environment. Based on the panel data of 282 cities from 2006 to 2018, this paper uses the non-radial DDF model to measure the urban carbon emission efficiency based on the establishment of pilot free trade zones, and establishes a double differential model to empirically analyze the impact of the establishment of pilot free trade zones on urban carbon emission efficiency and the impact mechanism therein. The results show that the establishment of pilot free trade zones can significantly promote the improvement of urban carbon emission efficiency, and this conclusion is still valid after a series of robustness tests such as PSM-DID and excluding other policy interference. Its mechanism analysis shows that the establishment of pilot free trade zones mainly affects urban carbon emission efficiency by improving urban energy efficiency and technical level, and promoting the optimization and upgrading of urban industrial structure. This paper provides useful policy enlightenment for promoting the green development of pilot free trade zones, achieving economic efficiency improvement and carbon emission reduction.