Nowadays, the consensus seems to be that Caste was definitely a thing before the Raj took over, but it was more fluid and regional, and was not the centralized, static hierarchy it is today. There were other power structures (feudal, religious, etc) that were not colored by caste, and competed with caste to triangulate people.

The British Raj took calculated steps to centralize, formalize, and entrench the caste system, shaping it into a form that is recognizable today, where it is strictly tied to opportunity and wealth.

It’s worth noting that is a common pattern of colonialism: to divide the colonized people against themselves along arbitrary, existing lines and elevate an arbitrary group, aligning the interest of that group with the interests of the colonizers. It’s a timeless and tragic human story.

I’ve only started researching this subject, so if anybody would like to correct or qualify anything I’ve said, I welcome it.