Mexico City’s infamous smog-inducing traffic ground to a brief halt yesterday as throngs of naked bicyclists took to its streets in an attention-grabbing bid to protest the Mexican capital’s car culture and promote their own rights, reports the BBC.

Dubbed the World Naked Bike Ride, an estimated 300 cyclists in various stages of undress wound their way past the city’s landmarks, ostensibly using their nudity to underscore their physical vulnerability against vehicles. “We fear going out every day and not knowing if we will return to our homes,” says one biker.

Mexico City has tried to promote bicycling, but millions of cars still cram its streets. “In Mexico it is a nightmare to ride a bicycle,” adds another rider. “It’s almost as if you don’t exist, you are a ghost.” The World Naked Bike Ride kicked off nine years ago in Canada as a way of promoting both the health and environmental benefits of biking, and has since been held in various cities around the globe.

Read more: Newser