“…Most of the literature refers to wastewater-based eco-efficiency research in China (Zhu et al, 2022;Zhou et al, 2020;Yu et al, 2016;Wang and Peng, 2021;Wang et al, 2022 ;Shi et al, 2021;Liu et al, 2022;Li et al, 2020;Huang et al, 2021;Hou et al, 2019;Chen et al, 2022b, etc.). There are few studies that analyze this indicator for some other countries.…”