Here is an article on the improving air quality in Bangkok. Still not the most clean air of course but apparently getting better.

(mod might want to move this to News section?)

http://www.iht.com/articles/2007/02/23/new...gkok.php?page=1

BANGKOK: Black smoke billowing from tailpipes into the humid, tropical air was once a Bangkok trademark. But a decade and a half after Thailand began a battle for better air quality, this erstwhile icon of smog has emerged as a role model for Asia's pollution-choked capitals, boasting considerably cleaner air than Beijing, Jakarta, New Delhi and Shanghai.

Some buses here still belch toxic vapor. And Thailand's political future is hard to plot as the country seeks to extricate itself from the tangled legacy of the military-led coup last September. Yet the skies in Bangkok on most days are blue, thanks to the work of a small, dedicated group of bureaucrats who pressed the case for cleaner air despite a history of weak, short-lived governments.

"There's a huge difference when you walk around the streets," said Jitendra Shah, a coordinator at the World Bank for environment and social issues in Southeast Asia who has worked in Bangkok since the 1990s. "Breathing is definitely easier."

Thailand's battle against air pollution provides a virtual how-to manual of environmental cleanup, say Shah and other air quality experts in Asia. Thai officials cajoled oil companies to produce cleaner fuel, used higher taxes to phase out the once-ubiquitous two- stroke motorcycles and converted all taxis to run on clean-burning liquefied petroleum gas. They overcame lobbying campaigns from the large, mostly Japanese-owned car industry and imposed progressively stricter emissions controls based on European norms (Thailand had no emissions standards before 1992).

If you'd look a few threads down you'd see this topic is already covered here.