This study investigates how environmental regulation implemented within the Basel III framework affects banks’ credit supply by combining a big-data bibliometric analysis, a structured review of the literature, and a case study. The bibliometric analysis maps key terms, research trends, and intellectual linkages in the literature and identifies Basel III–based environmental regulation as an emerging subfield. The structured review first synthesizes evidence on the credit-supply effects of Basel III capital regulation and develops an assessment framework based on three insights: the aggregate effect on overall credit supply may be limited; the impact varies across banks and borrowing firms; and the regulatory burden may be more pronounced for small firms and smaller banks. Using this framework, the study reviews evidence on Basel III as an environmental regulatory tool and derives implications for credit allocation. The case study further illustrates banks’ micro-level responses to regulation. We conclude by discussing policy considerations for designing and implementing such regulation.