NRI cant become the Managing director/whole time director, because the definition specifically says that Managing director have substantial power of the company and Whole time director means the director in whole time employment.
If NRI is appointed as Managing director, who will manage the affairs of the Regd Office?
It is practically not possible. It is something like that Bill Gates, Laxmi Mittal or Steve Jobs has been appointed as the Managing director of Reliance Industries Limited or some other company.
It is practical only in case of the company, whose Regd. Office is in India but have the branch office outside India and at least 75% of the revenue comes from the operation of that country.