Chiang Mai – Chiang Mai was ranked the most air-polluted city in the world for three consecutive days by iqair.com as of this morning, March 9th, with an average PM2.5 dust level higher than 200 µg/m3. Nearly 10,000 people with underlying respiratory conditions and allergies who are living in the northern province of Thailand have … Continue reading Chiang Mai ranked most air-polluted city in the world for three consecutive days after level of PM.2.5 dust particles reaches higher than 200