Can an Indian Company give loan to a foreign subsidiary below Government security rate?

It depends,

You'll likely want to have a tax lawyer look at this, as it can be a little complex.
-There are rules regarding transfers to foreign subs. Depending on how you structure it, the transfer can be deemed abusive.
-The foreign sub is also subject to their local rules, and that varies by country. Failure to meet the guidelines (account clearing, interest rate, etc) can do things like trigger a revenue event.
-Depending on the jurisdiction, there are other paths available to you, like "equity loans" where the funds are technically at risk, and the guidelines can be much easier to meet.

I can intro you to a good lawyer if you're interested. It's likely worth a few $ to get it right.