I have both USD and INR, and considering the interest rates are the same, which one is better to maintain the maximum currency in to yield maximum profit?
Investing in a foreign currency is a Bad Idea. Then you are vulnerable to currency rate fluctuations.
Keeping significant amounts of your money in the local currency is too a Bad Idea, if you are looking for maximum profit. Currencies yield relatively little interest.
Instead, you should be looking for more risky investments. The easiest of these are stock investments. If you diversify well and have a 20-year investment horizon, you can't fail, especally if you invest your money in gradual amounts (such as from saving a significant percentage of your income).
You can also look for opportunities to invest in real estate or forest. However, these require more knowledge and a larger initial sum to invest.
If you don't want to take high risk, you should balance your portfolio between local currency and stocks. Such as: 25% local currency + 75% stocks, 50%+50% or 75% local currency + 25% stocks. Take the amount of risk you afford to take.