This book, *Environmental Science and Sustainability*, has been written to bridge the gap between scientific understanding and practical action. This book is based on BCA and BBA  new syllabus (NEP 2020) prescribed CCS University, Meerut. It aims to equip readers with a clear, comprehensive foundation in environmental processes while highlighting the interconnectedness of ecological, economic, and social systems. By examining the science behind environmental issues and exploring pathways toward sustainable solutions, the book encourages informed decision-making and responsible stewardship.