The concrete mixer truck, which was returning from a construction site, ran over the two girls near a park at Harijan Basti in Sitapuri area of Dabri at around 11.30 am, a police official said.
Tamanna (4) died on the spot while her sister Sanjana (6), who was rushed to a nearby hospital by the police, succumbed to injuries during treatment, police said.
"Some construction work was going on nearby," the official said, adding, "It seems that the driver could not notice the two kids."
The girls' parents are from Nepal and were living here in a rented accommodation for many years. Their father Shyamu works in a private company.
A case has been registered and the truck involved in the accident was seized by the police. Efforts are on to trace the errant driver, police said.
