The Shiv Sena party, an ally of the main opposition BJP, said it had handed out 21,000 knives with three-inch blades to women in the city and surrounding areas and plans to distribute 100,000.
Mumbai police said they were examining the knives and considering legal action.
"This is a symbolic gesture," said Shiv Sena spokesman Rahul Narvekar, adding that a knife shorter than six inches in length does not fit the definition of a weapon. The party also handed out small bags of chili powder - apparently to throw into an attacker's eyes.
"It's only to pass a signal to eve-teasers, anti-social elements and perpetrators of crime against women that women are empowered and they can take care of themselves," Narvekar said.
Eve-teasing is a euphemism for molesting women.
"Don't be afraid of using this knife if someone attacks you," Ajay Chaudhari, running the knife campaign, was quoted by the party newspaper, Saamana, as saying.
"We have set up a team of nine advocates to protect you from any potential court cases that may arise."
A 23-year-old physiotherapy student was raped and beaten on a moving bus in on December 16 before being thrown bleeding on a expressway in New Delhi, dubbed India's "rape capital". Mumbai is generally considered a safer city for women.
The attack and the student's death two weeks later caused public outrage at the failure of the government and police to protect women from rising sexual offences in a country where one rape is reported on average every 20 minutes.
In response, more women are taking up self-defense classes and carrying pepper spray. A government commission set up to recommend revisions to India's sex crime laws this week said women who kill an attacker during a attempted rape should be able to plead self-defense.
Source yahoo news.