This is a very important question, because NRIs or non-residential Indians (NRI) are treated differently than normal residents from the point of view of tax treatments as well as with respect to financial transactions.

Thus, it becomes extremely important to define who an NRI is. So, an NRI is someone who resides outside India:

(a) for employment or vocation purposes; (b) under circumstances indicating an intention to stay outside India for an uncertain duration; (c) because he/she is deputed outside India for a temporary period in connection with employment.