As part of the Presidency of the Estonian Republic of the Council of the European Union, a flagship conference “Nature-based Solutions: From Innovation to Common-use” was organized by the Ministry of the Environment of Estonia and the University of Tallinn. EnRoute organized a side event on the conference with a focus on how the project can contribute to the knowledge base supporting nature-based solutions in cities. A summary report of the EnRoute event with the main outcomes is available here. In particular, EnRoute formulated a set of key messages for developing an updated version of the impact evaluation framework for nature based solutions.