A small number of scuba volunteers dive into the waters in central Stockholm, searching for waste items to retrieve to clean up the city’s waterways. Organized by Fredrik Johansson two years ago, volunteer divers and assistants on shore from Rena Malaren — ‘Clean Malaren’ — scour the floor of the Swedish capital's waterways, retrieving discarded boat batteries, bicycles, scooters, trolleys and other waste in a bid to improve the maritime environment.