Whether interin maintenance can be granted to a wife in case of the issue regarding her subsisting of marriage ?

Yes she is very much entitled to. For these situations I mean where the marriage validity itself is in question, the maintenance udner CrPC 125 is the best of course of action.

Just because the marriage was solemnized in a temple, does not mean that the marriage is void.  Is the other side challenging the contention of marriage?

For a marriage under Hindu Marriage Act Saptapadi is compulsory without which it can't be called as marriage so it's just a living relationship. So maintenance under Hindu mariage act is uncertain.

So the best choice is Crpc 125. Go through the below link for reference.

https://www.advocatekhoj.com/library/judgments/index.php?go=2010/october/13.php

This link also useful for you.

https://www.livelaw.in/a-victim-of-bigamous-marriage-is-entitled-to-maintenance-rules-supreme-court/

Yes @ Radhika Mehta

Were they no witnesses present at the time of marriage? Any subsequent event which can help you corroborate your story? 

Yes @ Radhika Mehta......We have lot of  witnesses but merely to prove this point that both the parties were living jointly in a single home upto 6 months. But, there are no witness regarding the solemnization of marriage because the girl was taken by her husband in an unknown place where they solemnized marriage....

The fact that you lived together is normally sufficient to establish the factum of marriage but 6 months is too short a duration to establish that. Your husband is challenging the very validity of your marriage or seeking orders to nullify the same??