Forest fires and agricultural burning have resulted in thick smog in large parts of northern Thailand. This has become so bad that many areas have been decalred disaster zones by the government, flights have been cancelled and large numbers of people have been treated for respiratory illnesses.

Unbelievably, instead of doing something about forest fires in Thailand and surrounding countries their solution is to attempt "cloud seeding" to make it rain!

More information, some photos and graphs here (http://www.thaibirding.com/news/news_pollution_in_chiang_mai.htm).