Population Growth–Decline Differentiation and Regional Inequality in the Yangtze River Delta: Implications for Sustainable Regional Development

During China’s transition toward negative population growth, spatial differentiation in demographic change has become increasingly pronounced, revealing deep-seated disparities that challenge sustainable development efforts. This study examines patterns of population growth and decline in the Yangtze River Delta (YRD) from 2000 to 2024 at the provincial level and for 2010–2020 at the city and county levels. Using decennial population census data together with annual series from provincial and municipal statistical yearbooks, the analysis combines population growth rates with inequality indices and spatial autocorrelation measures to identify disparities and redistribution dynamics. The results show a marked deceleration of overall growth, with natural growth turning negative and mechanical growth becoming the dominant driver. They also reveal a pronounced core–periphery structure in which core metropolitan areas and urban districts continue to attract residents, while many ordinary counties and peripheral cities experience persistent shrinkage. Population inequality remains modest between provinces but widens within provinces, driven mainly by divergence between cities and counties. These findings are consistent with SDG 10 and SDG 11 on reducing spatial disparities and promoting inclusive, sustainable urbanization, underscoring the need to balance metropolitan concentration with policies that strengthen demographic resilience in shrinking regions.