According to API JN Aher of Tilak Nagar police station, the incident took place on January 7 when the victim, 76-year-old Nilam Kochrekar doused herself with kerosene and set herself on fire, apparently after being upset with accused Rekha Kochrekar.
Rekha works in a private firm in the city. She used to come home late and the victim used to question her on this triggering frequent quarrels between the two.
Police said the two used to fight over petty issues and the accused had alleged that the mother-in-law was responsible for the feud between the couple.
The old woman succumbed to severe burns recently while undergoing treatment at a hospital, police said following which an offence under section 306 of the IPC was registered last evening.
However, no arrest has been made in this connection so far.