The Water Pollution Policy Regime Shift and Boundary Pollution: Evidence from the Change of Water Pollution Levels in China

Boundary environmental pollution and pollution spillovers are important issues for improving the water quality of trans-boundary rivers. This paper explores the empirical effects of the evolution of the pollution reduction mandates on boundary pollution by studying the change of water pollution levels (as proxied by pH, BOD, COD and NH3-N) of key state monitoring stations from 2004 to 2014. The empirical findings support the existence of boundary pollution and indicate the association between environmental policy and boundary pollution levels using propensity score matching, although the relation is conditional on which water pollution measure is considered. The pollution levels of monitoring stations on provincial borders are significantly higher than those of interior monitoring stations. The pollution of tributaries is more serious than that of the main stream, which was quickly reversed after the pollution reduction mandates changed. The improvement of the water environment showed great differences with the change of policy when we compare the water quality of monitoring stations in the upper reaches of provincial borders with the water quality downstream of provincial borders. Our empirical analysis finds strong evidence of strategic polluting across provincial borders. Local officials may manipulate pollution within their jurisdictions, and the overall pollution reduction target will exacerbate border pollution, whereas water quality inspection can reduce marginal pollution. Finally, we further validate the net impact of the policies on boundary pollution using a difference in difference (DID) approach.