Cities fight to clean "dirty air" as levels of pollution rise: WHOListen /
Several cities around the world are making a conscious effort to clean up their "dirty" air as the UN health agency warns about rising levels of pollution.
WHO's 2014 urban air quality database launched on Wednesday covers 1,600 cities across 91 countries.
Air pollution dramatically affects the health of city dwellers, the agency says, increasing the risk of heart disease, stroke, respiratory diseases and cancers.
Jocelyne Sambira reports.