Nature's resources are limitless, but human activity is destroying and polluting them daily. In addition, the effects of global warming and climate change have sped up the degradation of the ecosystem. Since the 1980s, there has been discussion about sustainability and sustainable development as a means of preventing this. These ideas are insufficient in the current technological era to offer practical solutions to the issue. As a result, creative solutions are needed to halt the world's expanding resource consumption as well as the negative effects of climate change and global warming. Resource conservation can be achieved by nanotechnology, which is the control of matter at the molecular level. The purpose of this section is to present the applications of nanotechnology in the fields of environmental impact and safety, sustainable water management, material recovery, and energy management. Each section is including a theoretical notion followed by a practical implementation. For example, for the section on sustainable water management, examples supported by nanotechnology will be tried to be described in an understandable way from nature-based solutions and circularity perspectives. Case studies were selected different geographical locations supported the information from the literature. This approach has also been applied to other chapters, and case studies have been presented from many different countries and regions, including China, Spain, Malaysia, and Brazil.