When the Norwegian Encore, the newest ship from Norwegian Cruise Line, launches in November, it will carry no plastic water bottles to offer guests.

The 4,000-passenger ship will instead carry Just Water, with a carton made mostly of paper, and a cap made of sugar cane. The company aims to switch its entire fleet over to the more sustainable drinking water option by the beginning of 2020, an effort that it says will eliminate six million single-use plastic bottles per year.

“We’ve established a goal to eliminate single-use plastics across the fleet, which is a substantial undertaking,” Andy Stuart, the chief executive of Norwegian Cruise Line, said. “The Just Water container goes as far as technology allows today in eliminating anything not renewable or recyclable in a container that will store water.”

The announcement by Norwegian, the third-largest cruise company , comes amid a flurry of new sustainability announcements in the travel industry as it and concerned groups — such as Prince Harry’s newly formed initiative, Travalyst — respond to pressure points that range from disaster recovery in the aftermath of massive hurricanes and increased wildfires to “flight-shaming” of those consumers who travel by plane, requiring a large carbon-emissions footprint.