The Role of New-Quality Productivity in the Sustainable Development of the Economic–Social–Environmental System: Evidence from 67 Ethnic Counties in Sichuan Province

Fostering and steering New-Quality Productivity (NQP) to underwrite the sustainable development of the Economic–Social–Environmental System (ESES) in ethnic-minority regions is both an intrinsic requirement and a strategic fulcrum for advancing modernization at the sub-national level. Despite growing policy attention, county-level evidence on how NQP translates into sustainability outcomes—and through which mechanisms—remains insufficient. Embedding NQP within a region-specific sustainability framework, this study first articulates the theoretical channels through which NQP can transform and sustain ethnic areas. It then exploits panel data covering 67 ethnic counties in Sichuan Province from 2005 to 2024 and applies benchmark regressions, multiple-mediator models, and spatial Durbin specifications to identify the mechanisms and impact footprints of NQP. Three core findings emerge: (1) NQP exerts a robust, positive effect on ESE sustainability that varies across geography, development stages, and sectoral structures. (2) Technological innovation, industrial upgrading, and optimized resource allocation all transmit NQP’s influence, with industrial upgrading displaying the strongest mediating power. (3) NQP generates positive spatial spillovers that extend its sustainability dividends to neighboring ethnic counties. These results sharpen the academic understanding of the NQP–sustainability nexus in ethnic contexts, expand NQP assessment frameworks, and furnish county-level policymakers with evidence to design differentiated strategies that align NQP cultivation with broader goals of regionally inclusive and sustainable development.