Eco-Efficiency Evolution of Water-Intensive Polluters in the Yangtze River Economic Belt: A Spatial-Temporal Analysis Using the DEA-Malmquist Index

Occupying a preeminent position as the globe’s most extensive economic corridor, the Yangtze River Economic Belt (YREB) serves as a crucial aquifer for 800 million individuals and harbors almost 50% of the country's paramount water-intensive contaminant producers. The ecological efficiency of these producers within the belt has increasingly come under scholarly scrutiny. Leveraging data from 2004-2012 encompassing 725 such manufacturers and employing the DEA-Malmquist index methodology, this research delineates the eco-efficiency trajectories of these water-centric pollutant producers, shedding light on their spatial-temporal dynamics across the expansive Yangtze Economic Belt. The results are as follows: (1) there’s a discernible enhancement in the eco-efficiency (ML) of these manufacturers situated within the YREB, predominantly propelled by technological change (TC) and shifts in technical efficiency change (TEC); (2) From a spatial perspective, notable disparities emerge in both technological change (TC) and technical efficiency change (TEC) among the belt’s upper, middle, and lower tiers. Intriguingly, the hierarchy for TC and TEC descends as follows: Lower > Upper > Middle; (3) Examining the spatial evolution nuances, 2004 witnessed eco-efficiency distributions ranking from Upper > Middle > Lower. Fast forward to 2012, a marked reconfiguration appears with a distribution pattern of Middle > Lower > Upper.