A PCR call was received 8:30 PM at Ambedkar Nagar police station regarding the incident from a neighbour.
"On reaching the spot it was found that Radha Devi (27) had strangulated her three daughters aged 8 years, 3 years and third girl was of 8 months. She also tried to kill herself by hanging to a tree behind her residence.
"She was taken to ESI Hospital at Okhala, from where she has been shifted to Safdarjung Hospital where her condition is stated to be critical," said a senior police official.
Police is yet to ascertain the motive behind the extreme act, however, Radha's neighbours claimed that her in laws desperately wanted a son and she was constantly nagged over the issue.
"Investigation is underway and all the claims were yet to be verified," the police official said.