How can city administrations tackle complex challenges like achieving climate neutrality, bringing about a mobility transition, and modernising governance? The "Data & Smart City Governance using the example of air quality management" project explores how data and digital solutions can address these issues. It focuses on collaboration between administrations, businesses, and civil society in data collection and processing to achieve outcomes that serve the common good. The goal is to develop a data governance concept for smart cities. It should define various roles, responsibilities, processes, and policies to meet the normative, organisational, and technical requirements of data-driven urban development. The living lab tested whether the developed approaches genuinely address the needs of all stakeholders and offer sustainable solutions.