There is an interesting connection between these three concepts. Reading anything about caste system, it is tempting to draw parallels with other structural injustices. Indeed, caste does look a bit like a class at first glance: there are producers and there are owners. One group is exploiting the labor of another for their own benefit. Simple, case closed! But one of the biggest false promises of capitalism is a chance to become a capitalist. The capital is constantly telling workers that they are very close to breaching this dividing gap between classes. If only they work a bit harder, they will also “make it”. And while the premise of this idea is, by itself, false, the caste system is definitionally a closed society with zero mobility between castes. The caste is an inherit characteristic, the idea of switching from one caste to another is as absurd as walking on water. There is no hope of better future for the untouchables. While a lot of capitalists do believe that they are definitionally (for example genetically) superior to workers, they must hide this believe to keep the illusion going, but in caste system there is no illusion, the superiority of one group over another is the point.
Race and racism seem to be a better comparison then. And Sujatha Gidla does indeed refer to American racism while trying to explain caste prejudice to the people outside of the system. But here the difference lays in religion. Christian faith has a shameful role in American slavery and racism as the gospel was used to justify these structures. But it was a sort of post justification. The slavery itself did not happen because of Christianity; the slavery happened, and Christianity was left to explain why it is actually good that it was happening. In caste system, there is an inherit, thousands-year-long connection with religion (not to mention that some people in some caste adhere to different religions). The caste system exists specifically as an oppressive religious structure.
Therefore, it seems to be a work done in vain, to try to compare caste system to the any structures more present and known in the “West”. Or rather one can compare but the comparison will never be perfect.