Deliverable 5.1 formulates the environmental models for each specific pilot (city) based on: the internal characteristics of each pilot, the availability of environmental data in each pilot, and the environmental science. The development of D5.1 was based on the overall approach that the environmental widget will help policy makers during policy implementation, by providing visualizations of meaningful environmental indicators relevant to each specific pilot, and during policy assessment, by providing visualizations of KPIs revealing the environmental impact of the proposed measure or policy for each pilot. In particular, D5.1 describes the environmental data model and the dependencies among certain types of measurements for the four pilot cities of CUTLER. It also identifies the various KPIs that will help the policy makers to measure the environmental impact by revealing insights around comparisons among different sensor readings or by visualizing change for a specific type of measurement.