Members of a team of researchers from the Center for Research and Advanced Studies (Cinvestav), who developed a method that converts solar energy into photovoltaic energy that activates a pump that sends "nanobubbles" into the water, check a pump at a trajinera boat as part of a project to clean the polluted waters at the canals of Xochimilco, in Mexico City, Mexico August 20, 2021. Picture taken August 20, 2021. REUTERS/Toya Sarno Jordan