The purpose of this textbook is to provide a comprehensive understanding of the basics of Environmental Science to undergraduate students pursuing various courses in science, engineering, and social sciences. The book covers a broad spectrum of topics, including the structure and function of ecosystems, biodiversity, pollution, climate change, renewable energy, and sustainable development. The book also delves into the role of government policies, laws, and regulations in protecting the environment and promoting sustainable practices. Overall, this textbook is a valuable resource for anyone interested in gaining a comprehensive understanding of the fundamentals of Environmental Science. We hope that this book will inspire students to take an active interest in environmental issues and equip them with the knowledge and skills to contribute to sustainable development.