MUMBAI (AFP) - At least 27 people died and 17 were injured in western India on Thursday when a local bus slid off a mountain road into a valley, police said.

"The driver lost control after a tempo (three-wheeled vehicle) rammed into the bus along a sharp turn, causing it to fall into a 80-metre valley," local policeman Sangram Singh Nishandar told AFP.

The accident happened near a popular picnic spot in the Thane district of Maharashtra state, 160 kilometres northeast of Mumbai.

Around 140,000 people were killed in Indian road accidents in 2012 - which works out to 16 an hour - according to the government's National Crime Records Bureau.

Bad roads, speeding vehicles and poor driving were among the contributing factors.