A government sponsored harvest festival.
This was 2017, unclear if this event will be held every year and according to what schedule. http://m.dehong.gov.cn/index.php?a=show&catid=70&typeid=67&id=1833 This was an earlier event at the beginning of November http://www.zhglc.com/lslc/tslc/content-23-6175-1.html