The sand-ladden lorry driver, a woman passenger of the private bus and a two-wheeler rider were killed in the mishap.
The bus dragged the lorry for more than a KM as its mangled rods got hooked onto the other vehicle, police said.
Later, the bus knocked down a two-wheeler rider, who died on the spot while the woman passenger was thrown out of the bus and died.
Seven passengers who sustained injuries had been admitted to a hospital, police added.