A new report says the sport of tennis faces very significant problems with integrity. The report said the problems, involving issues like fair play and honesty, are most notable at the lower levels of the sport. It said a major cause was a sharp increase in internet betting, with some players winning money by losing to their opponents on purpose. The Interim Report of the Independent Review of Integrity was released last week after a two-year independent investigation. It said that investigators had not found widespread corruption at the highest levels of tennis worldwide. But it did find that there is evidence of some issues at these levels.