A Hybrid Multi‐Phase DEA Window‐ GRA Approach to Assessing the Dynamic Performance and Environmental Trade‐Offs of the Container Shipping Industry

The global container shipping industry underwent significant transformations from 2016 to 2023, shaped by post‐Hanjin bankruptcy consolidation, COVID‐19 disruptions, and the onset of mandatory decarbonization. Throughout these phases, container shipping lines (CSLs) had to maintain high efficiency while striving to improve their environmental footprint. To understand how these targets intertwined, this study employs Data Envelopment Analysis (DEA) Window to evaluate operational efficiency evolution (RQ1) and Gray Relational Analysis (GRA) treating CO 2 as an undesirable output to assess environmental trade‐offs (RQ2) among nine major CSLs. The findings reveal upward efficiency trends in the post‐Hanjin phase (2016–2019) driven by alliances, followed by significant volatility with widened performance gaps during COVID‐19 (2020–2021). Efficiency stabilized but diverged during the decarbonization phase (2022–2023). While the trade‐off between efficiency and emissions intensified during disruptions, it diminished as the industry transitioned toward greener standards. Notably, comparison between GRA and DEA results indicates that GRA penalizes high‐DEA performers with elevated CO 2 levels, exposing hidden environmental costs. The study concludes with managerial strategies for green investments, policy recommendations for equitable regulations, and theoretical advancements in multi‐method efficiency assessments. This research underscores the industry's shift toward sustainable resilience, offering critical insights for stakeholders navigating future uncertainties.