As a result of increasing public concern about pollution in the city, its surrounding areas, and the province itself, the Governor of Chiang Mai, Viboon Sanguanphongs, has issued a public order prohibiting burning of all kinds in open areas. Rubbish incineration and the cutting down of trees are also prohibited. The order is highly specific, and is being sent out to all local administration organisations, and also to government agencies in the province.
Prohibited activities include waste incineration, the burning of twigs, leaves, agricultural residue and the burning of areas of forest. Officers are being sent out to instruct the public in alternative ways of eradicating or recycling waste, as recommended by the governor. The province has also designated certain areas as forest fire protection zones. It is hoped that officers will be able to persuade local people to abandon their traditional burning practices and replace them with new methods of waste management in order to produce fertilizer. Any breaches of the new public order will be severely dealt with under the law.
Pollution is caused by incomplete combustion processes forming carbon particles, combined with dust from roads and fields. During the dry and hot seasons, prevailing weather conditions favour the formation of early morning smog and air pollution, as an “inversion layer” of colder air traps warm air below it, preventing it from rising and dissipating polluting particles.
Recently, the Meteorology Department reported that the lessening of a depression over Thailand had caused increases in daytime temperatures in the upper regions of the country, but that the weather was still cold, with cloudy conditions, exactly the conditions which encourage the formation of an inversion layer and the resultant pollution. Airborne pollution is able to travel great distances at altitude as a result of prevailing winds; an example of this being the huge decrease in already unsatisfactory air quality caused by the massive forest fire on the Burmese border during last year’s hot season.

Source: Chiang Mai Mail