<p>This study examines the synergistic effects and underlying mechanisms through which environmental regulation promotes pollution reduction and carbon mitigation from a comprehensive production process perspective. Using the implementation of Cleaner Production Standards (CPS) as a quasi-natural experiment, we apply a difference-in-differences approach based on the China Industrial Enterprise Database. We find that enterprises that have implemented CPS reduced emissions of sulfur dioxide (SO₂), chemical oxygen demand (COD), and carbon dioxide (CO₂) by 0.100, 0.066, and 0.067, respectively, suggesting notable synergies in pollution and carbon reduction. Mechanistic analysis reveals that CPS operates through three channels: source prevention, process control, and end-of-pipe treatment. At the source prevention stage, enterprises that have implemented CPS function through energy conservation and pollution prevention. During the process control phase, they enhance total factor productivity, providing support for the Porter Hypothesis. In the end-of-pipe treatment stage, these enterprises improve pollutant treatment efficiency by upgrading pollution control equipment and treatment capacity. Industry-level analysis indicates that sectors that have implemented CPS facilitate resource reallocation among enterprises. Heterogeneity analyses further reveal pronounced asymmetries and sector-specific differences in policy impacts. These findings provide empirical evidence and policy implications for optimizing environmental regulation design and further promoting synergistic effects in pollution and carbon reduction.</p>