Bangkok, Sept. 10 -- The capital city of Bangkok and four northern provinces have been officially declared "pollution control zones" as part of Thailand's systematic effort to tackle rising levels of hazardous PM2.5 dust.

At a meeting of the National Environment Board (NEB) on September 8, chaired by Deputy Prime Minister Prasert Jantararuangtong and attended by Bangkok Governor Chadchart Sittipunt, the NEB designated Bangkok, Chiang Mai, Chiang Rai, Lamphun and Mae Hong Son as control zones in response to worsening air quality.

Officials said the designation is intended to streamline and strengthen enforcement of anti-pollution measures, with smog levels expected to rise during the winter and dry seasons.

In northern Thailand, new con...