In this WHO Science in 5-episode Dr Etienne Krug, Director of Social Determinants of Health, shares examples of cities that are taking action on greener more sustainable transport that can also help keep people healthier and safe.  For example, Mexico City, Mexico has increased cycling lanes while making roads safer Cali, Colombia has sent out bike doctors to help repair bikes and Lusaka, Zambia created safer routes for children to get to school.