President-Elect Trump is a "natural experiment". Back in the mid-1990s, the top 5 academic journals were filled with such applied micro papers. Suppose President Trump ends the H1B Visa program. There is a large group of talented people who would remain in their home nation because they couldn't work in the USA. Indian engineers would be a large subset of these affected individuals. If 100,000 Indian engineers a year remain in India, won't this boost the short term stock of human capital in India? If Lucas 1988 is the right model of economic growth, then won't cities with increased numbers of these engineers boom?
Now, you might ask --- if the engineers help India so much --- why won't their wages be high there and they will choose to remain there and would turn down the opportunity to move to the U.S? The externality argument made by Lucas is that proximity to skilled people raises the productivity of an economy. The individual skilled do not receive all of the benefits they convey to others so there is a positive externality here that each individual engineer ignores when he/she migrates to Silicon Valley.
This boom may only be temporary if the next generation of Indian engineers do not study as hard because they recognize that they can't move to Silicon Valley. There is also a cross-elasticity effect that there are other destinations for engineers to move to if they can't move to the USA. Will they go to China or Germany?