This book is an outcome of the 35th International Conference EnviroInfo 2021, held at Humboldt University Berlin, organized by the technical committee for Environmental Informatics of the German Informatics Society. It presents a selection of papers that describe innovative scientific approaches and ongoing research in environmental informatics and the emerging field of environmental sustainability, promoted and facilitated by the use of information and communication technologies (ICT). The respective articles cover a broad range of scientific aspects including advances in core environmental informatics-related technologies such as earth observation, environmental modelling, big data and machine learning, robotics, smart agriculture and food solutions, renewable energy-based solutions, optimization of infrastructures, sustainable industrial processes and citizen science, as well as applications of ICT solutions intended to support societal transformation processes toward the more sustainable management of resource use, transportation and energy supplies. A special focus lies on the question how environmental informatics can contribute to achieving the United Nations Sustainable Development Goals. Given its scope, the book is essential reading for scientists, experts and students in these fields of research.