Hello Sahil,

Best books for GATE Environmental Science and Engineering are listed below.

Environment At a Glance (For PG Entrance Exams, UGC-CSIR NET, GATE, ICAR-ARS/NET, Civil Services and UG Classes of Panjab University by Saranjeet Kaur

Reasoning and Aptitude by Nem Singh

Basics of Energy & Environment: ESE 2021: Prelims GSEA by MADE EASY by MADE EASY Editorial Board

GATE GENERAL APTITUDE & ENGINEERING MATHEMATICS

Environmental Engineering Sewage Waste Disposal and Air Pollution Engineering - Vol.2 by Santosh Kumar Garg

Wiley Acing the GATE: Engineering Mathematics and General Aptitudeby Anil Kumar Main

To get more information about GATE Environmental Science syllabus go through below mentioned link.

https://engineering.careers360.com/articles/gate-syllabus-for-environmental-science-and-engineering

Hope this information will help you.

Good Luck!!