Quantitative Study on the Synergistic Effect of China’s Plastic Restriction Policy from 2008 to 2025

Since 2008, the Chinese government has been intensively implementing policies to control plastic pollution. This study employs text mining and scientific statistical methods to quantitatively analyze 223 policy documents spanning the period from 2008 to 2025. The novelty of this study is associated with the analysis of temporal coherence, content complementarity and subject collaboration in the field of policy aimed at limiting the use of plastic and the development of a universal methodology for the design of complex environmental policies. The results show that policy releases peaked in 2008 and 2020. The average number of policies issued by each province in the eastern region is the highest, with 6.8 items. In terms of policy content, A3, B3, and C3 are the most prominent policy objectives, means and safeguard measures, respectively. The synergy of policy content indicates that market-oriented policies have stronger implementation, for example, the synergy strength between A2 and B2 is 0.7467. The synergy between legislative and enforcement policies is insufficient. For example, the synergy strength between A1 and B1 is only 0.2903. The regional synergy decreases from southwest to northeast. The northeast region lags comprehensively. In terms of time, the similarity of policy texts between 2021 and 2023 remained stable (0.3256–0.3666). The three-dimensional framework offers an approach to policy synergy evaluation. It indicates that the core governance framework of the Chinese Government has strong continuity. This study also has positive value for global environmental protection, such as reducing plastic pollution.