Police said that the incident took place last night when Rajni strangulated her daughter Drishya and then hanged herself inside her room.
Rajni, who married Rinku three years ago, lived with her husband in Dwarka Sector- 15 of west Delhi.
According to police, she was depressed for the last few months and the reason behind the extreme step of Rajni was yet to be ascertained as no suicide note has been recovered from the spot.
Officer also said that a case has been registered in this regard and further investigation is on.