“…Researchers have lately applied DEA as a favored method in measuring the eco-efficiency (Emrouznejad & Yang, 2018;Kao, 2014;Sueyoshi, Yuan, & Goto, 2017) of plants (Lozano, 2017;Sueyoshi & Goto, 2012), industrial parks (Fan et al, 2017), provinces or regions (Song, Peng, Wang, & Zhao, 2018;Wu, Zhu, Ji, Chu, & Liang, 2016;Zhang, Bi, Fan, Yuan, & Ge, 2008), and industrial sectors (Shao, Yu, & Feng, 2019). Chen et al (2018) and Gong et al (2019) evaluate the efficiency of major shipping carriers considering the negative impact of emissions. Gong et al (2019) used input variables, such as the number of ships, total assets, capacity, employees, capital expenditure, and fuel cost to produce desirable (revenue and lifting) and undesirable (CO 2 , SO X , and NO X ) outputs.…”