According to police, Krishna Devi, 42, had been suffering from depression after her nephew eloped with a girl from the neighbourhood some days back.
A heated argument broke out this evening between Devi and her husband over the issue which prompted the former to shoot herself with a country-made gun, police said.
The source of the pistol used to commit the suicide is being investigated, they added.
Devi lived with her husband, son and two daughters at their residence in Sonia Vihar area.