Evaluating the Effectiveness of Single-Use Plastic Ban Policies on Municipal Solid Waste and Environmental Quality: A Difference-in-Differences Analysis

Single-use plastic (SUP) bans have been widely adopted across urban jurisdictions to curb plastic pollution and improve municipal waste management. This paper evaluates the causal impacts of municipal single-use plastic ban policies enacted between 2018 and 2022 across 64 urban jurisdictions using a staggered Difference-in-Differences (DiD) quasi-experimental design and the Synthetic Control Method. Analyzing panel data spanning 2016 to 2024, our econometric estimates show that mandatory SUP bans reduce per capita municipal plastic waste generation by 38.4% (p < 0.001) within three years of enactment. Event study dynamics confirms pre-policy parallel trends. Environmental quality monitoring reveals a concurrent 26.2% reduction in macro-plastic litter density in local waterways. However, compliance cost analysis highlights transitional financial friction among retail SMEs, underscoring the need for targeted alternative material subsidies.