There is no particular books for the preparation. For JNU M.Sc Environment Science, the questions will be of MCQ type. The questions will be in two parts.

Part I: This will have questions from the different areas of Science and

Mathematics at the 10+2 level.

Part II: This will have questions, in the areas of Physics, Chemistry,

Mathematics, Geology, Botany and Zoology at the B.Sc. level.

Also solve previous year’s question paper.

You can also refer the link mentioned below for more details

https://jnu.ac.in/admission/e-prospectus-2019-20.pdf

Hope it helps you.