On some of European waterways a fleet of kayaks have been fitted with an unusual accessory: A trash can. These bright green boats are free to rent, but volunteers are required to work for their trip by collecting floating waste. The initiative is the brainchild of GreenKayak, a Denmark-based environmental NGO with a mission to clean up the continent's canals, rivers and lakes. Volunteers can take to the water in one of the project's colourful two-person kayaks, equipped with paddles, life vests and trash pickers. While enjoying the tour, kayakers can pluck garbage from the water and fill the onboard trash can. Although still in its infancy, the scheme aims to address a growing global challenge. According to UN figures, about 13 million tonnes of plastic waste ends up in the world's oceans each year, the majority of it fed along rivers from land-based sources. This pollution damages marine life which reduces biodiversity and can potentially harm human health. Since the initiative launched in 2017, volunteers have collected over 15,000 kilograms of floating waste from Europe's waterways and the project is growing. The scheme, which started in Copenhagen is now operating all around Denmark as well as Norway, Ireland, Germany, and Sweden.