Four people were killed when the bus they were travelling in was swept away in floodwaters in Orissa's Rayagada district while four more died after being struck by lightning in Cuttack city, officials said on Sunday.
The driver lost control while the bus was passing over a flooded bridge, a police official said.
The bus with around 40 passengers plunged into a rivulet after being carried away by floodwaters near Maikanch village, some 470 km from Bhubaneswar on Saturday evening.
Four people, including a baby, were killed and 12 injured in the accident.
In a separate incident, at least four people died and two sustained burn injuries on Saturday night when lightning struck a slum in Cuttack, over 25 km from Bhubaneswar.
The injured are undergoing treatment in hospital and are out of danger, a district official said.
Heavy rain has been lashing several part of Orissa since Saturday morning, affecting normal life in many areas.
Titilagarh town in Bolangir district recorded maximum of 108 mm rainfall on Saturday. State capital Bhubaneswar recorded 8.5 mm, an official of the Bhubaneswar meteorological centre said.
The met office said most parts of the state would see heavy to very heavy rains in the coming couple of days as well due to a low pressure area formed over Bay of Bengal.