As for the PDF download, I couldn't find a direct link to download the 13th edition of Ecology and Environment by P.D. Sharma. However, I can suggest some possible sources where you may be able to find the PDF:
First published by Rastogi Publications, this book has become a staple for B.Sc. and M.Sc. Environmental Science students, as well as for civil services aspirants. Dr. P.D. Sharma presents complex topics like ecosystem dynamics, biodiversity conservation, pollution control, and environmental impact assessment (EIA) in a clear, structured manner. As for the PDF download, I couldn't find
Week 5 — Applied Ecology & Current Issues As for the PDF download