SANTIAGO (NYTIMES) - Chile will become the first nation in the Americas to ban retail businesses from using plastic bags, an initiative aimed at protecting the country's 4,000-mile (6,437-km) coastline.

The measure, which Congress approved unanimously this week, gives large retailers and supermarkets six months to comply.

Small and medium-size businesses, including neighboyrhood shops, will have two years to abide by the new rules. In the meantime, they may hand out up to two plastic bags per client.

The measure is President Sebastian Pinera's first legislative victory since taking office in March. Pinera expanded the scope of a Bill introduced last year by his predecessor, Michelle Bachelet, that sought to prohibit the use of plastic bags in more than 100 coastal towns.

"We are convinced that our coast imposes an obligation to be leaders in cleaning up our oceans," said Marcela Cubillos, the environment minister.

Almost 80 municipal governments around the country have already adopted restrictions over the past few years, while some beach and lakeside communities have outright bans.

Chileans use more than 3.4 million plastic bags a year, according to the environment ministry, and most get dumped in landfills or make their way into the ocean.

The measure represents Chile's latest effort to be a model on environmental issues. Congress passed legislation in 2016 to reduce waste and promote recycling, and Chile has overhauled its electricity sector in recent years to rely more heavily on renewable energy sources.

"It is a positive step," Flavia Liberona, director of the environmental group Terram, said of the ban. "It opens the door to move forward and discuss other related problems, like the use of plastic food packaging and recycling."