Swiss television SRF reports that one cart bumped into another one on the roller coaster, likely because of technical problems with the brakes. One woman was severely injured in the crash yesterday night and was hospitalised while four others were treated at the scene.
Separately, a man was injured when he was thrown to the ground while exiting a merry-go-round. He was hospitalised.
SRF reported that police were investigating the incidents.
The Basel Autumn Fair is Switzerland's biggest fair with around 500 stands and amusement activities. It lasts through November 12.