though, i have prepared it from dr Farooq's book, book is poorly written but still recommending you to go for it, don't entirely relay on this book, just get concept and then update and incorporate some knowledge from internet sources, you can do it because its better to start preparation from some ordinary book rather than wasting your time for waiting some good quality book, while in case, if u had not started the preparation of environmental sciences and still confused and have a chance to opt any other book than i can say you can opt some other subject because i m just telling you on behalf of my personal experience, that i found environmental sciences quite difficult, elaborated, lengthy, and tough subject with core concepts and depth, it requires expenditure of time to understand and to be covered..remaining is your choice, if you are still committed to opt it than i am always available for your help, do ask frankly where you stuck in your preparation.