Is there anything that that would be obvious to someone from India but not a white guy from the U.S. that a co-worker is being shunned or mistreated in the workplace on account of their caste? Even knowing what caste each of one's Indian coworkers are in could be helpful in some ways and detrimental in others.
(My impression of the Indian people I've worked with is almost entirely positive, and I generally consider them to be a mistreated class already just because so many of them are here on an H1B visa and therefore could potentially be kicked out of the country if they happened to be laid off, which no doubt is in the back of their minds when considering whether or not to work through the weekend. The employee-employer relationship is edging close enough to slavery to make me uncomfortable.)