Impact of policy combinations on carbon emission performance: evidence from China

Enhancing carbon emission performance was crucial to achieving carbon neutrality goals. However, few studies have explored the driving mechanisms of carbon emission performance from the perspective of policy combinations. This study combined new energy demonstration cities and low-carbon cities as the subjects of policy combinations and analysed the impact of these two policy combinations on carbon emission performance. This study integrated the superefficiency epsilon-based measure model and the propensity score matching difference-in-differences method. We utilized panel data from 2007 to 2020 covering 271 Chinese cities to investigate the effects of these two policy combinations on carbon emission performance. First, this study employed the superefficiency epsilon-based measure model to measure carbon emission performance. Subsequently, the propensity score matching difference-in-differences approach was used to assess policy effects. The results indicated that the combination of these two policies significantly enhanced carbon emission performance, with a combined effect surpassing that of independent policy impacts by 48.47