In the Sixties and Seventies, they left India on scholarships to go to the US. Today they head leading-edge science at the world's top institutes - and have no plans of returning home.
But India has realised it can still pick the brains of its scientific diaspora.
In response to an invitation sent out in March by the Ministry of Science and Technology, 128 India-born scientists and technologists from 13 nations - over half from the US - have said they will come back for two to 12 weeks every year for a three-year period to pursue long-term research with Indian scientists and train young students.
The ideas sent in range from agriculture to aerospace. These include mass diagnostic techniques for thalassemia, aircraft performance problems, absorption of carbon dioxide from power plants and the development of cancer and heart therapies.
Applications have been received from various universities and multinationals including Stanford University and Boeing Company. The Department of Science and Technology (DST) is sifting through them. DST secretary T Ramasami said the department would select projects 'critical to Indian needs' that could expand beyond the three-year duration to start new research centres. The DST will fund Rs 7 lakh per project within India.
Niche experts who have responded include IIT-Kharagpur alumnus Swapan Chattopadhyay, an associate director with the Jefferson Lab, Virginia, who heads a 350-strong team in its accelerator division. "A small fraction of us who chose pure science found ourselves not served well by doctoral programmes in India,'' he said. He realised he would be more useful to his profession and to India by being abroad as he could "exchange ideas, students, and grand designs unhampered more easily".
A national screening committee will study proposals for the 'durability' of the proposed partnerships, and the PMO is monitoring the project. The best collaborative ideas will be selected soon.