Choked by traffic, Bangkok revs up to beat air pollution

BANGKOK - There are two pictures Thai air pollution expert Supat Wangwongwatana likes to show whenever he talks about Bangkok's transition, in a little over a decade, from a city blanketed in smog to one boasting clear blue skies.

The first, taken in the mid-1990s, shows the skyline of downtown Bangkok. Most buildings are in silhouette, shrouded in a thick layer of haze. The Baiyoke Tower, back then the city's tallest building, was still under construction.

The second, taken a decade later from a similar angle, looks dramatically different. The sky is blue, the clouds are visible, and the buildings bathed in sunlight.