At least four people were killed and six others injured when a vehicle carrying them skidded off the road and fell into a ravine in Kharkai area of Upper Dir on Wednesday morning. Local police and Rescue 1122 said the ill-fated station-wagon vehicle was carrying passengers from Dir when it skidded off the road and fell in a ditch. Police said slippery road conditions due to snowfall and overloading of the vehicle caused the accident. The medical teams of Rescue 1122 Dir Upper shifted the dead and injured to Barawal, Timergara and Dir Upper hospitals. Police said the identity of the deceased and injured was being ascertained.