The incident took place around 3.30 PM when S S Chawla was returning home in his car from his relative's house in Rajendra Nagar, a senior police official said.
As he stopped at the traffic intersection, three persons, riding a motorbike, stopped beside his car and one of them knocked on his car's window, he said.
When Chawla refused to roll down the window glass, one of the accused broke it with a brick while another shot at him and fled.
"A case of attempt to murder has been registered in connection with the incident but the motive is not clear yet," DCP (Central) Parmaditya said adding efforts are on to identify the trio.
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From preliminary investigation, it appears to be fallout of personal enmity as Chawla had a pouch containing a bundle of cash but the assailants did not touch that suggesting it to be a well-planned act, an official said.
But Chawla's relatives are learnt to have told police that he was not involved in any personal rivalry.