How does inland Free Trade Zones in China trigger industrial green transformation? Evidence from policy text mining

The green development of inland industries has become increasingly critical in China with the large-scale relocation of industrial enterprises to China's central and western regions. As exemplars of high-quality development, inland Pilot Free Trade Zones (PFTZs) play a pivotal role in advancing the green transformation of industries in inland areas. To address potential subjectivity in traditional mechanism analysis, the study conducts text mining on 249 policy documents related to inland PFTZs to identify key policy focuses, constructs the Policy Modeling Consistency index, and ultimately ascertains the specific channels through which inland PFTZs influence industrial GTFP. The empirical results reveal that: (1) The establishment of inland PFTZs significantly improves GTFP, with heterogeneous effects in terms of resource endowments, environmental regulations and city size. (2) Text mining combined with PMC-LDA index identifies three mediating pathways including infrastructure optimization, technological innovation promotion and government efficiency enhancement. (3) The Spatial Durbin Model confirms the existence of spatial spillover effects on neighboring cities at different distances. These findings provide theoretical insights and policy implications for promoting industrial green transformation through PFTZs in inland areas, and offer a text mining perspective for identifying the mechanisms of inland PFTZs on GTFP.