Despite having a clear understanding of traffic pollution and its impact way back in the 1990s, air pollution in many urban areas and cities across the world continues to get worse. Some solutions are: create pedestrian only areas, especially where there are lots of people; implement low emission zones, areas for low, or zero, emission vehicles only; set up areas where diesel vehicles are not allowed -schedule deliveries outside of busy periods; modify diesel vehicles with technologies that improve their emissions; switch bus fleets from diesel to gas, alcohol, hydrogen or electric power; target the worst 10 percent of vehicles (which can cause up to half of all the pollution). On a recent trip to Delhi, for example) I noticed that trucks can't enter the city during the day. http://www.innovationfuturespecialist.co.uk/gallery/traffic-pollution.html