What a stupid statement!
If there is no oxygen, as the phrase above suggests, then there would be no people alive in Chiang Mai.
I have lived here for many a long year in CM and cannot understand the over-reaction that idiots people like you push.
Yes there is pollution, as in most areas of the world, but there is also oxygen in CM, as there is in the rest of the world, for all of us to breath!
I suggest you stick to facts and quit the dramatic hyperbole!