I have worked with Indian workers for the last couple of decades. There are cultural differences, there are knowledge and critical thinking differences, and most important, there are environmental differences.
I have worked side by side with Indian people in the US and Canada. They are generally Ok to work with them, because they have acquired some western culture and dissed some of the Indian culture. However, working with Indians in India, oh boy! That's a freaking mess.
For starters, they are not hiring the best and brightest in India. Those are already in the US, Europe or Canada. Not only that, they are hiring the bottom of the barrel, the ones willing to work for what is considered "low wages" in a country of low wages. So you get youngsters with no experience, or old jackasses. Then you have the turnstile working at max speed, with people abandoning their jobs after just 3 months, because the job/salary su-ks.
One important cultural difference is that Indian workers never say NO to a request or question, because they are afraid to be replaced if they don't know or can't comply. So if you ask them if they understood your request, they will say YES, even when they didn't.
In general, even with the Indians working here, I never found Indian people being smarter than us. I see some of them more motivated to learn or to succeed than us, but not able of "learning faster", or to come with new ideas. However, I am of the opinion that WILL is more powerful than SMARTS, and that would explain the success of so many asian families in US.
Environmental differences are BIG. A few years ago, at Ford, in the middle of a "crisis", the guy supporting the issue from India left the call because "the bus was leaving". Americans were baffled, because they didn't undertand. Of course, living in this country, where the public transit works, where we have Uber, taxis, where we are used to drive own car, Americans could not understand it. However, the guy was from a small village in India, where there is no transit, he has no car, no Uber, no taxi, and the company is the one providing transportation. The guy miss this bus, he cannot come back to his house for another 24 hours.
So a guy that might not have power that night, that possibly doesn't have indoor plumbing or toilet, that doesn't earn a lot of money, doesn't care for the urgency of a project or incident.
Now, on top of that, add the office politics...