... role in achieving this. Since the majority of Asian countries are adopting existing technology rather than creating new technology, one of the central tasks in developing urban transport is finding ... refinement, cost reduction through economies of scale, development of supporting infrastructure, marketing, and penetration of the existing fleet.6 Heywood and 4. The Air Pollution in the ... number of other cities are showing increasing interest in CNG as a substitute for diesel to reduce NOx and PM10 levels in the air. However, at the same time, a vigorous debate is taking place,...