The deceased have been identified as Mohini(40), her daughters Saniya (10) and Runjhun (7 months), her sister-in law Mala (37) and the SUV driver Rajesh (40), they said.
The family was returning from a social ceremony from Saket Nagar locality. On the way back, a speeding tractor hit the SUV they were travelling in, they added.
Seven others, including Mohini's husband, who were gravely injured in the accident were taken to a hospital, police said.
The bodies have been sent for post-mortem and investigation has been initiated, they said further.