According to reports, Pooja, a resident of Bhajanpura in east Delhi, had an altercation with the accused, Munshi Yadav, who then shot her in the face. She reportedly died on the spot.
Munshi, who was allegedly drunk, was caught by the bystanders and handed over to the police, according to reports.
There was a police post at about 100 metres from the scene of the crime, and a PCR van arrived in about five to ten minutes, eye witnesses told the Press Trust of India (PTI).
Police said the victim and the accused knew each other and the incident appeared to be a case of personal enmity, PTI reported.
An eyewitness named Rajesh Kumar said, "These two people were having an argument for quite some time. I heard a gun shot and when I turned, the girl was on the floor and screaming. We caught him (Munshi) there only."