Environmental conservation is crucial in the current scenario. Among various environmental challenges, sustainable waste treatment stands out as a key knocking area. Scientists are actively engaged in developing novel technologies that are both highly proficient and cost-effective. One such promising approach is nanotechnology, which offers potential applications in this field. Nanotechnology represents an advanced field of scientific and technological knowledge, offering innovative solutions across various specialties at a nanoscale of 1–100 nm. Due to the unique properties of nanomaterials (NMs), nanotechnology finds applications in diverse sectors such as the environment, agriculture, food, medicine, information technology, and energy conversion. It is increasingly being used for environmental protection, particularly in the treatment of water and wastewater, waste management, and remediation of groundwater and soil. However, the production of NMs and nanoproducts is expected to increase significantly in the coming days, making effective nanowaste management a critical concern. Concerns about the infiltration of nanoparticles into ecosystems, as well as their subsequent effects on biota, have been present since the early days of the manufactured NMs industry. Unfortunately, estimating the concentration of nanoparticles in the environment is highly challenging, and the assessment of risks posed by NMs released into ecosystems is still in its early stages. Environmental nanotechnology provides innovative solutions to various environmental challenges and supports sustainability through advanced nanotechnological products and processes. Nanostructured materials, such as nanocatalysts, metal–organic frameworks, functionalized NMs, nanocomposites, carbon-based materials, nanocoatings, nanolubricants, nano-silica, nano-zeolites, etc., provide significant potential for applications like greenhouse gas reduction, wastewater treatment, and environmental remediation. This chapter aims to summarize nanotechnology-based strategies for combating climate change, reviewing the long-standing environmental impacts of new nanocompounds, and promoting sustainable approaches to address environment-related challenges. It also emphasizes the need for responsible management of nanowaste, identifying concerns and priorities for the future.