Chiang Mai had the world’s worst air pollution with 198 microgrammes of particulate matter 2.5 micrometres and less in diameter (PM2.5) per cubic metre of air over the 24 hours ending at 4am on Sunday, according to a leading pollution website.
The IQAir.com website ranked the northern province the most polluted on earth based on the amount of fine dust measured over the 24-hour period. Trailing in Chiang Mai’s dust were Baghdad with 193µg/m3, Delhi 180µg/m3, Jakarta 174µg/m3, Kolkata 171µg/m3 and Lahore 170µg/m3.
People in Chiang Mai have been unable to see the iconic Doi Suthep mountain for weeks due to the thick, toxic smog.
On Sunday morning officials detected 13 hotspots in Chiang Mai. PM2.5 accumulated above the borthern city there because of its basin landscape, stagnant air and smoke haze from nearby farmland and forest blazes.
The Meteorological Department predicted storms in the North from Sunday to Tuesday that may alleviate the pollution. It also expected winds over the next week to relieve thick smog across much of the country.
The Geo-Informatics and Space Technology Development Agency (Gistda) reported 1,061 hotspots in Thailand on Saturday while there were 4,363 hotspots in Myanmar, 2,868 in Laos, 1,182 in Cambodia, 647 in Vietnam and 32 in Malaysia.
In Thailand, 661 hotspots were found in forests and a further 192 hotspots on farmland. The northern province of Mae Hong Son had the most hotspots in the country – 127 – on Saturday.
Apart from Chiang Mai, unsafe levels of PM2.5 were also reported in Mae Hong Son, Chiang Rai, Tak, Nan, Phayao, Lamphun, Lampang, Loei, Phrae, Uttaradit, Kanchanaburi, Chaiyaphum, Phetchabun, Uthai Thani and Phechaburi provinces.
PM2.5 was measured at 53.1 µg/m3 on average in Bangkok over the 24 hours to 4am. Thai authorities set the safe threshold at 50 µg/m3.