The mishap took place at Pursari area between Nandprayag and Chamoli this afternoon when a mini bus coming from Karnaprayag with 29 persons on board fell into a 50-metre deep gorge, killing four on the spot and leaving the rest of them injured, they said.
Two more persons died at a hospital in Gopeshwar where the injured were admitted.
Prima facie the accident seems to have been caused by over-speeding, police said.