I didn't hear of it either until I noticed large groups of Indian-origin devs and managers (mostly at older companies such as IBM, Oracle, etc), and somehow only the 'upper caste' folks would get promoted and be invited to happy hours and such. How much that can be attributed to inter-personal relationships and professional competence as opposed to outright discrimination, one will never know but a pattern does emerge. It's never in your face discrimination, just subtle favoritism towards one's group.

Mind you, this happens with people from the same Indian state as well. They'll often speak in their regional language during meetings even though not everyone speaks that language, which simply goes on to alienate that team member. (This has happened to friends of mine at T-Mobile and Intel)

"marriage sites have done more to break cast barriers in india"

Not sure if I agree with you there. It has brought to light just how prevalent that kind of thinking is. It's a common trope on Indian matrimonial websites how users have a list of requirements (Looking for fair skinned, Hindu upper caste, etc). Maybe that has helped break cast barriers by bringing it to light, I don't know, but it was really surprising when I came upon it for the first time.

I was thinking the problem is limited to India and will not get carried over to US or tech industry in India.

Was not expecting to see caste system in US too and was doubting if it was real. I had heard one story where adults in US were introducing themselves with caste. This story talks about even the kids are introducing with their caste. What are we teaching kids?

Every Indian should read this. It doesn't matter if you discriminate or not, the person suffering is not dealing with just you but lots of people. Even if a small percentage discriminate that is bad enough for that person to feel vulnerable for long time.

Counter-point: many cases of sexual harassment seem to occur over a long time, where the problematic behavior is known or suspected widely -- it's just that nothing is done.

Consider: I don't care for celebrities or Hollywood, I'm not American, but I knew Weinstein for being a pig long before he got cancelled, mostly through offhand jokes from comedians. I didn't really know how big of a deal in his business he was, I just knew that everyone seemed to know that he was a pig. So when he finally got cancelled, what surprised me is that I sort of thought that he already had been.

I've known of few instance of much less prominent harassment (sexual or otherwise for that matter) at the periphery of my social circle, and it was a similar phenomenon. I believe there is a type of people that does that kind of things (narcissists), the problem I suspect is that they tend to also be good at manipulating people so that they can keep doing damage for a long time.