Environmental Science is one of the most important areas of research and study in present time. Its application in every aspect of our life has also increased, its importance manifold. Keeping this in view, almost all Indian universities have introduced it as a compulsory course. The present book is intended to suit the needs of students pursuing Environmental Studies for undergraduate and postgraduate courses of all the branches of Higher Education in various universities. The general reader will also find this book a useful introduction to the subject. By design, greater attention has been given to present a balanced approach to all aspects of ecology and environmental sciences. This book is intended for teacher trainees of LT, BTC, and BEd classes, teacher educators and teachers teaching at senior and junior levels. It is so designed as to cover the courses of ?Environmental Science? of LT, and Bed classes. Sincere attempts have been made to present the matter clearly, briefly and simply.