According to police, the driver could have lost control of the vehicle as the bus was overcrowded.
The deceased were identified as Anaar Singh (65) and Nirmala Bai (45), both residents of Barotha village in Dewas district, police said.
Among the 77 injured, 59 persons were admitted in government-run M Y Hospital in Indore. Five of them are in serious condition. Seventeen others are undergoing treatment at Dewas, while one injured was admitted to a private hospital, police said.
A case was registered in this regard and further probe is on.