It is difficult to imagine our life without light. We are so accustomed to it that sometimes we don’t even remember its key significance. You can philosophize for hours on the existence of light and darkness, light in darkness or darkness in the light. In architecture, this theme has existed since the inception of architecture. It was always credited with divine meaning. Lighting effects always saturate the interior, connected and unified spaces, created and transformed. Currently, daylight often performs a purely utilitarian function - it illuminates the space, the place of residence of people. And this is what is really necessary for a comfortable interaction with the environment for a person and even, elementary, for his health. Its second function is the transformation of interior / exterior space due to the interaction of daylight with shadow, color and shape. In this work, we decided to look even deeper. To think about light, as an instrument of a larger factor, how it can affect our world, make it better or help cope with a global problem? Thus, we present a project that can help to solve the problem of water pollution through interaction with daylight. The project proposal consists of a water treatment base and transportation crystals. The base is located on the shore of the reservoir. The first stage of water purification takes place here. Energy for work comes through solar panels located on the inclined walls of the base and due to the energy of the water (water flows). The crystals, flying up to the base, take water, charge with energy and fly into the air. In the process of transportation, the second stage of water purification with the help of DAYLIGHT takes place. Due to process of photosynthesis, algae that clean the water propagate. Due to the sun they multiply. Excess weight enters the lower compartment, where the biomass decays. Subsequently, with further actions, we get environmentally friendly fuel for the crystal. Helium helps keep the crystal in the air, which fills the space between the inner and outer walls of the volumes. The outer shell of the crystal is transparent, then during transportation, the lower cavity of the inner shell accumulates solar energy on its walls and can illuminate its movement at night. So that at any time of the day, people can get access to water.