Fairly sharing environmental targets in China: A multicriteria decision-making framework for provincial PM2.5 target allocation.

A fair allocation of air quality improvement responsibilities to subnational governments is critical to achieving China's national air quality targets. However, the target allocation process still lacks a transparent and broadly accepted decision-making approach. This study develops a multicriteria decision-making framework to distribute national fine particulate matter (PM2.5) reduction targets across provinces, integrating three ethical principles-responsibility, capability, and potential-to promote equity and attainability. We use China's 14th Five-Year Plan (FYP, 2021-2025), which mandates a 10 % national reduction in PM2.5 concentration, as a case study to quantify provincial targets under various preference scenarios and compare them with the official allocation, illustrating how policymakers' choices shape target outcomes. Our findings show that under equal weighting of all principles, provincial reduction targets range from 7.7 % in Gansu to 22.1 % in Jiangsu. However, the results are highly sensitive to policy preferences. For instance, prioritizing capacity assigns Shanghai the most stringent target of 27.2 %. Notably, varying preferences can lead to differences of up to 10 percentage points in reduction requirements for provinces like Beijing and Shanghai, highlighting the challenge of balancing fairness and feasibility in target allocation. Furthermore, our analysis reveals that China's official allocation of PM2.5 targets in the 14th FYP leans toward a capacity-oriented preference, imposing larger burdens on wealthier regions. We recommend that future strategies place greater emphasis on the responsibility principle, supported by financial transfer and interregional coordination mechanisms, to address disparities. In addition, stricter targets for northeastern and western regions, as well as the Fenwei Plain (FWP), are advised to prevent persistent inequalities in air quality and enhance local environmental governance. While tailored to China, this framework is adaptable to other regions grappling with air pollution, offering a reproducible model for equitable burden-sharing.