Asia’s urban population is rapidly expanding. It is expected that by 2020 as much as 50 % of the ASEAN population will reside in cities. Combined with continued economic growth, this trend is proving to have various adverse impacts on the environment, particularly in terms of air quality and greenhouse gas emissions. Cities and urban regions contribute to approximately 70 % of global CO2 emissions. In many ASEAN cities, the transport sector is the main source of greenhouse gases as well as of air pollution.
Increased air pollution is partly a reflection of the greater volumes of traffic and production of goods. However, not only road traffic but also maritime transport matters. Shipping and associated port trans-shipments affect air quality and cause local environmental problems, for example through polluting stretches of the coast.