The mess at the IIT-Bombay campus in Powai houses two varieties of plates, the round steel thali and a rectangle one. The round is picked up by vegetarians. If in a moment of ignorance, you, the non-veg eater picks up the round plate, you don’t say, “Oops!” and place it back on the rack. You deposit it straight into the wash basin area. It will be cleaned before it once again reaches the next vegetarian student on campus. It’s not earmarked in any rulebook. But it is a rule, unsaid and immovable. 

The marginalised students belonging to Scheduled Castes and Tribes (SC, ST), and Other Backward Castes (OBC) know that they must eat off the rectangular thali, even if by choice they have adopted a plant-based diet. Years of conditioning and having to manoeuver the relationship between caste and food 
makes them informed.