As anyone who has coughed their way through a traffic jam in a Southeast Asian city will tell you, urban traffic congestion is one of the region's major challenges. This study from Sri Lanka has focused on one key aspect of this problem - the health impacts of diesel vehicles in the country's capital, Colombo. Assessments were made of the make-up of the city's traffic and the potential health impacts of various diesel emission sources. It was found that particulate pollution (much of it coming from diesel vehicles) is linked to health problems that may he costing the city up to LKR 22 billion per year.