This paper adopts the fixed-effects model to estimate Eq. (1), Table 2 reports the baseline estimation results. It can be noted that there is a significant negative correlation between PGDP and CEEI. The greater the PGDP, the more disadvantageous to improve energy efficiency. To be specified, the results find that the energy efficiency development indicator decreased 3.3 percent for each unit increasing PGDP. The estimation results in column (1) only control the city and year fixed effects. The