This updated technical paper compiles information on mitigation benefits and co-benefits of policies, practices and actions for enhancing mitigation ambition in urban environments. It also includes examples of options for supporting the implementation of these policies, practices and actions. The paper is based on presentations and discussions that took place at the technical expert meeting on mitigation, including the collaboration forum, held during the forty-sixth session of the subsidiary bodies, and on a review of the latest literature. It is an update of the technical paper contained in documents FCCC/TP/2014/13 and Add.2, and FCCC/TP/2015/4 and Add.1 and 2. For the updated technical paper on mitigation benefits and co-benefits of policies, practices and actions for enhancing mitigation ambition in land use, see document FCCC/TP/2017/9.