Analyzing Coupling Coordination of Pollution and Carbon Reduction with High-Quality Economic Development: A Case Study of China’s Yangtze River Economic Belt

Promoting the synergy of pollution and carbon reduction (PCR), as well as accelerating high-quality economic development (HQED), are the two major tasks of China’s current economic development. Thus, it is crucial to achieve a deep integration between PCR and HQED. We first construct the indicator system of PCR and HQED, and use the entropy method to assign weights to the indicator system. The coupling coordination model often portrays the level of coordinated development between systems. We apply this model to measure the synergistic relationship between PCR and HQED in 108 cities of the Yangtze River Economic Belt (YREB) in China from 2006 to 2021.We further analyze its spatial-temporal characteristics, regional differences, and convergence. The results reveal that the coupling coordination degree (CCD) between PCR and HQED in the YREB increases from 0.4234 in 2006 to 0.5832 in 2021. A higher CCD reflects a better coordinated developmental relationship between the two subsystems, and the relationship between the PCR and HQED shifts from on the verge of being uncoordinated to barely coordinated. Meanwhile, the CCD of the YREB shows a trend of decreasing downstream, midstream, and upstream, with significant spatial positive autocorrelation characteristics. Moreover, the overall differences in the CCD of the YREB from 2006 to 2021 show a fluctuating trend, with larger contributions of inter-regional differences and intra-regional differences. The convergence model reflects whether there is a tendency for the coupling coordination differences to narrow. Finally, the model indicates that there is no σ convergence but exists β convergence in the CCD of the YREB. Convergence is fastest in the downstream, followed by the midstream, and slowest in the upstream. The study reveals that the CCD of the YREB is increasing and has significant positive spatial correlation characteristics. It could utilize inter-city synergies, implement integrated strategies, and promote synergies between PCR and HQED in accordance with local conditions. Our findings provide empirical evidence and policy references for effectively promoting the deep integration of PCR with HQED.