Brain Drain refers to migration of skilled people to other countries.
This is more severe in developing nations including India.Even though our country has better educational institutions like the IITs and IIMs people often opt to go abroad and pursue their career.To prevent this,countries like Russia laid restrictions on the number of migrants to other countries but later gave up
As per books brain drain means after getting education from the native land if one go to abroad for his services, then it called..
If self development or self growth is called Brain Drain then any country or India has to adjust with it. A man/women genrally takes higher education to get good job, for self development and for this if he move to abroad (bcz there is lack of oppotunities in his/her native land or else..), i don't think it is a wrong thing.
When educated and brilliant people leave their own country and start contributing and become part of another country we see brain drain which happens to a great extent in India because of poor management and poor socio economic conditions ..