This book is divided into four chapters; it is prepared to give a lucid picture of the environment, its degradation and conservation to university students. Chapter 1 provides an understanding of the environment and ecological principles that are basic to organism interactions and the flow of matter and energy in ecosystems. The nature of food chains and how they affect the flow of matter and energy are discussed. Chapter 2 focuses on Natural resources, their use and exploitation. The main thrust in the chapter is on conservation of these resources and the impact of human activity on natural ecosystems. Chapter 3 describes different biogeography zones of India and emphasis is on the need of biodiversity, threats to biodiversity and its conservation. Chapter 4 deals with water pollution, marine pollution, air pollution. This chapter also explains the global warming, ozone depletion and acid rain in general. Environmental ethics and environmental laws have been discussed that have become very important in context of environmental degradation.