We visited Chiang Mai in April, just before the Songkran Festival and the air was so hazardous that the authorities were considering cancelling the festival. It definitely tarred the experience of Northern Thailand for me and I’ve had bad times in this country before, but I wanted to give it another go. Unfortunately, it was just as we crossed the border from Myanmar to Mae Sot that the pollution hit peak crisis point. We checked Twitter and there were mixed reviews as to whether it was too bad to visit or not, but we went anyway as we had to…