US Based NRI's - Liquid Funds better than FD

Happen to stumble upon below article:

As per the article; Liquid funds instead of NRI FD, saves more tax if you are US based NRI. Provided rates are same & $ appreciates every year.
Just curious if any one has tracked these options?..

I was under the impression that if you are in the US as an NRI you are not allowed to invest in Indian MFs. I may be wrong though.