This report first introduces the background and objectives of the third phase research of the urban environment project on the transportation sector. It provides an overview of transport and environment in Asian cities. It illustrates the rationale of the scoping of focus policy areas and selection of case studies. It also consists of six case studies and one comparative analysis on policies related to transport and environment in Asian cities. It summarises the findings of the studies and discusses the barriers and opportunities of the air pollution control in the transportation sector, concluding with the perspectives for future research.