Two and three wheelers will remain as important modes of transport in many Asian countries and cities. This report aims to provide policymakers and city authorities in Asian countries and cities updated information on the issues, policies, and regulations regulating to emissions and the increasing use of motorized two and three wheelers. It makes use of the results of activities and studies conducted y the Clean Air Initiative for Asian Cities (CAI-Asia) Center and the UNEP Partnership for Clean Fuels and Vehicles.