Gurvinder Singh, who was driving the car, was arrested from the spot.
Singh, 32, was driving his personal Tata Indica car, which rammed into the senior Bharatiya Janata Party leader's Maruti Suzuki SX4 on the side he was sitting, police said.
"We are investigating whether he (Singh) jumped the red light in the morning," Delhi Police Joint Commissioner M.K. Meena told IANS.
The police have registered a case against Singh of rash and negligent driving, causing death.