The incident took place around 10 pm on August 18 when, the accused, Pradeep alias Monu, along with his associates, was going to Bindapur from Vikaspuri in a car.
Pankaj Gautam and his friend Dinesh were on a motorcycle and a quarrel ensued between the two sides over allowing passage for the car to pass, said Deputy Commissioner of Police (Crime) Bhisham Singh.
The accused, Pradeep, fired at Gautam in Om Vihar, Phase-III, Uttam Nagar, the police said. Gautam was severely injured and admitted to a hospital.
Pradeep was arrested from Dwarka on August 25, the police said, adding that a .32 bore pistol loaded with one live cartridge was seized from him. His car was also seized.
In 2013, he, along with his associates, was involved in a case of robbery, the police officer said.
A reward of Rs 50,000 was declared on information leading to his arrest. Subsequently, he was arrested and sent to jail. After his release, he again got involved in criminal activities in west Delhi, the police said.