THICK black smoke spews out of the exhaust pipe of the Kampung Rambutan-Kota public bus, and engulfs passengers waiting at the Salemba bus station in Central Jakarta. Some cover their faces with handkerchiefs, while others simply hold their breath. Everyone tries to avoid inhaling the noxious fumes. The scene is hardly memorable. It's a common sight on Jakarta's streets.

Exhaust from motor vehicles are a major contributor to air pollution i