State police official D.Y.S. Chauhan says another 14 people in the two vehicles were injured in the accident Saturday near Badaun, a town in Uttar Pradesh state.
The bus driver was among those killed.
Chauhan said on Sunday that the van's driver lost control of the vehicle as it went through a mound of sand. It then crashed into the bus.
Badaun is 175 miles (280 kilometers) southwest of Lucknow, the state capital.
More than 110,000 people die annually in India in road accidents caused by speeding, bad roads, overcrowding and poor vehicle maintenance, according to police.