With the maturing of the US technology industry, and the rapid expansion of India as a center for software programming and business process outsourcing, thousands of Indian engineers and managers — many of them US-educated and working on Route 128 or in California’s Silicon Valley — are opting to go back to their homeland.

The trend is raising fear of a brain drain. Some business leaders are worried that the immigrant Indian entrepreneurs who helped fuel the US technology boom might now start companies in India, and take whole classes of jobs with them.

”It could deplete the stock of educational and scientific talent that we have here,” said Alan Tonelson, a research fellow for the United States Business & Industry Council, a Washington trade group for small and midsized manufacturers.

American-educated graduates from other countries, from Israel to Taiwan to Ireland, also have launched companies in the United States. But the Indian connection is unique because of the intense engineering focus there.

And returnees starting businesses in India, unlike those in smaller and richer countries, can tap into a large and growing domestic market, and into a pool of low-cost skilled workers.

For some Indians, the reasons for the exodus are personal. Returning expatriates may have aging parents, or they may want their children raised in the Indian culture. But with the explosive growth of India’s economy, cities such as Bangalore or Hyderabad increasingly are seen as new magnets for ambitious technologists — offering an intoxicating mix of hefty raises, multiple job postings, and rapid career advancement, no longer the norm in Cambridge or in San Jose, Calif.

More here.