Q: How can I locate Suitable Time Server to Serve as Reference Clocks.

A: There are lots of free time servers available to the public.  Since you live in Mumbai I am not sure how many of those are viable options for you.  However you can use the free servers at ntp.org.

The pool.ntp.org project is a large system of distributed time servers.  These are publicly assessable.  Please see below links for more information.  

Also if public NTP servers are hard to come by in Mumbai, maybe you will consider joining one of your servers to the NTP pool.

For more information on the pool.ntp.org project please see their homepage here:

English version here:

For information on how to use the pool as your time server see here:

And for information on how to join the pool, see here:

For people in The United States of America ntp.org is a good choice.  Also the U.S. Navy runs some free NTP servers which can be found here:

I hope this helps, but unfortunaelty there is no way I can answer your question more precisely.  Maybe someone reading this can give some more information in the comments.