Students visit a theme exhibition on drug control during an activity on the International Day against Drug Abuse and Illicit Trafficking in Sanhe, north China’s Hebei province, June 26, 2019. (PHOTO / XINHUA) WASHINGTON – The root cause of the US fentanyl abuse is “in itself,” and Washington is “purely wrong” to “groundlessly criticize China and spread disinformation,” said the Chinese Embassy in the United States on Thursday.…