Hazardous pollution levels in northern Thailand have left the historic city of Chiang Mai choking under thick smog, with locals worried about the impact on tourism -- and their health.
"Chiang Mai that I remembered back in the day was a beautiful and cheerful city," says one tourist. "But coming back here this time and seeing all the smog, it hides the city’s beauty, and makes me wonder if I’ll ever come back here again if there’s still pollution like this."