Mexico City's Mayor Miguel Angel Mancera is handing out plastic whistles. A half-million of them. At three bucks a pop, he's hoping that women will use the whistles to scare off harassers on the packed public transportation system.

When the plan was announced this summer, it received a flurry of scathing criticism and mocking memes on social media. But city officials are moving forward and have been handing out the whistles by the thousands at subway and bus stops.

At the Zapata metro station in the southern end of Mexico City, the buses and subways are packed at midday, the perfect conditions for harassment, say women. Nearly everyone has a story.

"They tried to grab me from behind," says Vanesa Sumana, 20. Luckily she spoke up and was on the subway with her dad.

"I said, 'Dad they're grabbing me,'" says Sumana. "Just then my dad turned around and punched the guy."

Hilda Magana Ramirez, 64, says, it doesn't matter your age, the harassment is constant, especially when passengers are squished like sardines in the subway.

"The men come behind you and start grabbing," says Magana, as a group of women listening to her nod in agreement.

According to Mexico's National Statistics Institute, nearly 3 million sexual attacks occurred between 2010 and 2015. The attacks range from groping to rape. A recent survey by the city showed that seven out of 10 female passengers had been harassed on buses and subways.

That is where the city is targeting their whistle giveaway. Earlier this week, officials boarded one of the pink colored women-only buses to spread the word about the whistles.

Mexico City's governmental secretary, Patricia Mercado Castro told the passengers it's time for women to speak out against the problem.

"The whistle is there to help women break the silence and make noise when someone harasses them," says Mercado.

So far, the critics of the whistle plan have been making the most noise. Since he began handing out the whistles earlier this summer, the mayor has received a barrage of criticism on social media and in the press. One tweet asked if the Mayor had future plans to distribute maracas to combat corruption, or was going to pass out the favorite noisemaker of soccer fans, the vuvuzela, to crack down on extortion.

Jimena Soria of GIRE, a women's reproductive choice group in Mexico City, says the problem needs more serious solutions.

"The amount of violence against women doesn't deserve such a simple answer," she says. And she adds, just giving women whistles puts all the burden on them to protect themselves. "I don't think you should be carrying a whistle around your neck so you will be safe," she adds.

She says men need to be held responsible for their actions and the macho culture that enables such harassment needs to change.

City officials insist the whistles are just one part of a comprehensive plan to combat violence, which includes the installation of panic buttons in subways and buses, and sensitivity training for police.

Officials hope to distribute a half-million whistles by Dec. 1.

Vanesa Sumana, the 20-year old business school student, says she'll use her whistle for sure.

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