The impact of the fall was so huge, the bus was broken into pieces, a police official here said.
The bus was going from Rishikesh to Ghat and fell off a steep slope into a 300 m-deep gorge at about 12:45 pm, when it was around half a kilometre away from its destination, he said.
Many passengers on board the bus are still missing, he said, adding search was on to find them. Search and rescue teams have meanwhile pulled out seven injured passengers from the mangled remains of the bus and rushed them to a hospital, he said.
The bus was owned by Garhwal Motor Owners Company. Most of the passengers of the bus are said to have been hailing from Ghat block, he said.