As drug use has soared 57 percent in the last four years among the under-21 set in in Hong Kong, authorities are increasingly seeing ketamine abuse as a problem. The animal tranquilizer made popular on the American rave circuit in the 1990s is cheap in the Chinese city, thus appealing to people as young as junior high school age. While cops have focused on clubs in the past, they've had to widen their dragnet. K abuse happens even in public parks. CNN reports.