Decomposition and attribution analysis for assessing the progress in decoupling industrial development from wastewater discharge in China

China's strategy of greening industrial development aims to decouple industrial growth from industrial wastewater discharges (IWDs). This study combines decoupling analysis, decomposition analysis, and attribution analysis to support this goal. First, the decoupling analysis is employed to explore the degree of decoupling between industrial growth and IWDs in China, as well as across 30 provinces, from 2000 to 2015. Next, a decomposition analysis focusing on the change in industrial wastewater discharge intensity (IWDI) is performed to reveal the factors influencing decoupling trends. Then, attribution analysis is used to attribute contributions of these factors to different regions. Our decoupling results indicate an increasing decoupling trend between industrial output and IWDs in China in the past 15 years. Meanwhile, there is a convergence in decoupling degrees among provinces. Decomposition results reveal that water intensity plays a dominant role in promoting decoupling, while the wastewater discharge coefficient negatively impacted decoupling before 2005 but contributed to decoupling later on. Regional attribution results indicate provinces in South China have exerted more efforts in both water saving and wastewater treatment during the study period. Water scarce provinces in North China performed better in terms of water saving, while more developed and water-rich provinces in South China performed better in wastewater treatment. This paper suggests targeted policy methods at province level.