Standard Publishers has released official e-book versions. While not "free," they cost roughly ₹300–₹500—a fraction of a single pizza. You get searchable text, bookmarking, and the ability to highlight.
If you are a civil engineering student or a environmental engineering professional in India, the name needs no introduction. His book, Water Supply Engineering (often studied alongside Environmental Engineering by B.C. Punmia), is a staple for university exams and competitive tests like GATE, IES, or state engineering services. water supply engineering p.n. modi pdf download
A quick search for the term reveals that thousands of students are looking for a digital copy. Standard Publishers has released official e-book versions