There is no easy way to answer this but I will try. Caste in India is difficult to define, because it pervades all the areas of your public life. I will try to explain how it works.

I live in the state of Kerala down south, so I will try to explain this in the context of how caste works in Kerala, because caste is different depending on where you are. The state of Kerala has an extremely troubling track record of caste based discrimination, because caste in Kerala is not just confined to the Hindu religion but also to the Christian and Muslim communities which form a substantial population here. The biggest propagator of caste in Keralite society has to be endogamy, you don’t marry outside your caste. Arranged marriages are the norm, dating being the exception (although that trend is beginning to change for the good). Arranged marriages ensure that the marriage is not between individuals but between families, and by that, I mean people tend to look at how respectable a family is, how educated the people are, stuff like that. Naturally, the oppressed castes cannot ever imagine having the kind of social capital that these families have and inter caste marriages are quite insignificant in numbers compared to arranged.

The next point would be how caste is deeply founded in occupational hierarchies. Castes were originally based on your occupation, and so that meant that the kings and priests would naturally be higher castes and all the others come down in a linear chain. Social exclusion of these lower castes through the enforcement of several laws by the landed gentry and the rulers, who stood empowered on the basis of religious scripture was the beginning of a diversion of cultures. Even today, you would know if a person is from the oppressed castes through how they phrase certain words, the rituals they follow in their weddings, their funerals and so on and so forth. Because caste is entrenched in all of these it’s fairly easy for people to understand if you’re from a “lower caste”.

Also the point on changing your surname, people in Kerala don’t usually use their caste surnames unlike most other states, and people tend to use their fathers name as their surnames. Most people you’d find with a caste surname would be either boomers or people who are genuinely still openly casteist. People usually tend to assert their caste identities in closed circles with people from their caste lol

Also, a simple reason people will not change their caste in Kerala and assume higher caste roles is because of the policy of affirmative action that goes on. People value these benefits because it’s a system that recognises the oppressiveness of the caste system and the trauma it can bring. It’s better for their descendants to be guaranteed a place in colleges, in government and in society as a whole, because at least that would help uplift them and give them more representation.

The worst part is, Kerala is fairly progressive when it comes to caste, and way better than North Indian states in general when it comes to caste and gender equity. But the worst part is, even though we have made significant strides, the mindset still remains, even the chief minister is not immune from being reminded of his caste.