The woman sustained injuries on her nose, said police.
A woman in Uttar Pradesh's Sitapur has alleged her nose was chopped off by her in-laws after she filed a case of triple talaq against them.
The archaic practice of instant divorce by uttering "talaq" thrice by Muslim men has been banned under a new law that provides for a three-year jail term.
"We got a complaint that a man gave triple talaq over phone. Both families were called and a counselling attempt was made. When the matter was not resolved, we filed the case under the relevant section of the triple talaq law," a police officer said.
"The woman was thrashed. She is in a hospital now. She was injured on her nose," the officer said.
The woman's mother Sharifun Nisha alleged her daughter was thrashed by her in-laws after she went to the police to complain about triple talaq.
"I went to the police station to file a triple talaq complaint for my daughter. Her in-laws threatened her after she did not withdraw the case. They beat her up," Ms Nisha said.
The woman's brother-in-law alleged his family used a sharp weapn to "cut off her nose". "They also hit me with a stone," he alleged.
The bill to ban triple talaq, which failed the Rajya Sabha test last time, sailed through the opposition-dominated upper house on July 31.