[linlucas]

I’m sorry that you had to go through this. I’m east Asian myself, and I often cant tell the ethnicity of other east Asians (Korean, Chinese...). So how does Indians determine the caste of other people? Is it by the lightness of their skin?

[devdas]

Usually name, accent, dialect, food habits. It's not visible upfront, but a few minutes of conversation will get that information.

There is a skin colour bias, but that isn't about caste (darker skin is a sign that you have to work in the sun, which signals poverty and being of a lower economic class).

[ves]

last names encode a lot of information. Skin color / features etc can also be informative.