Smog returns in Upper North

Song Klinprathum, director of the royal rainmaking operations centre in the Upper North, said six flights were set to try to induce rain to reduce haze in Chiang Mai and Mae Hong Son.
Banpote Khantasen, a natural resources and environment official in Chiang Mai, said haze was thick again, partly because of a cold air mass blanketing the North. Air quality at Chiang Mai City Hall was 132 micrograms per cubic metre, just over the ‘safe’ level of 120 mg.
The province has strictly controlled outdoor burning and kept monitoring the situation. The level of dust particles normally reaches its highest level from March 2226 every year.
The haze has reemerged in Chiang Rai also. Particulate matter smaller than 10 microns was measured at 337 mg per cubic metre in Mae Sai and 202 mg in the provincial seat.
Visibility dropped to less than one kilometre and municipal officials mobilised fire trucks to spray water in the air to ease the haze problem.
Chiang Rai Governor Thanin Supasaen said the smog stemmed from forest burning across the border and a cold air mass in the area, which kept the haze in the lower atmosphere.
He ordered local authorities in four border districts to sprinkle water in an attempt to block haze from the neighbouring country.