Dharmendra, a resident of Madangir area, was rushed to AIIMS hospital but was declared brought dead, police said.
Seventeen people suffered injuries on their heads and limbs and were taken to AIIMS, Safdarjung and RML hospitals for medical care, they said.
The condition of two of them is said to be serious while others were discharged after first aid.
The owner of the vehicle, Balbeer Singh, was driving it when the incident took place. He is on the run.
According to the police, the incident took place at around 9:15 AM when the Road Taxed Vehicle (RTV), carrying 25 government employees, overturned after one of its front tyres separated from it at Defence Colony flyover.
The bus was hired by government employees to ferry them from their residences in South Delhi to their offices and back.