Budapest faces challenges in mainstreaming climate considerations into governance and in aligning public-private collaboration for climate action. Cap4ClimB addresses these barriers through capacity building, climate budgeting, and cross-sectoral tools. By co-developing training programmes, climate budget tagging, and private sector collaboration models, the city aims to create institutional mechanisms that enable inclusive, systemic transformation. The project also promotes exchange with other Mission Cities to enhance replicability and shared learning. Objectives Mainstream climate action in city governance Build municipal and citizen capacity Develop a climate budgeting toolkit Strengthen collaboration with the private sector Ensure systemic and equitable climate transition ECT = Enabling City Transformation