Badminton, like tennis, is a racket sport that is played by either two players or two teams of two players each. The object is for you or your team to get to 21 points first. You score a point whenever you successfully serve the shuttlecock and your opposing team commits a fault, which means that the team fails to appropriately return the shuttlecock.
Assuming one cares for their teeth by brushing regularly, saliva may smell bad because there are millions of bacteria present in the mouth. Bad smelling saliva or breath can be indicative of a tooth abscess, or a systemic illness such as diabetes.
A dry mouth is a stinky mouth. That's why your breath is worse in the morning; your mouth produces less saliva as you sleep. Saliva is the enemy of bad breath because not only does it physically wash bacteria and food particles away, but it also has antiseptic and enzymes that kill bacteria. Chewing gum stimulates saliva production (in addition to covering up the odor with some kind of scent). Mints do not encourage saliva production.