my passport binding has become loose. Do I need to get new passport or this is fine?
There are many similar questions here about replacing worn or damaged or lost Indian passports (getting a new passport with a new passport number), and reissuing Indian passports (getting a new passport with the same number as your old passport). You can search for those questions and answers using the "Search on Travel" box at the top of the page.
Assuming the data, photo, and chip are present and readable, the answer is a matter of opinion. If you're confident the booklet will not further deteriorate and won't come apart in your pocket, then travel with it.
An immigration officer (from any country) might tell you its too worn or damaged to use, but if the data, photo, and chip are present, will probably not refuse you entry or passage. An immigration officer from a country other than India, however, is unlikely know the difference between "replacement" and "reissue" as set forth in Indian law.
If you're not sure or are nervous about its condition, have it reissued.