Last year, an Indian PhD coworker explained to me about the princely states. When I told him European slave traders took my ancestors to British Guiana to slave for them and the queen, he was deeply touched and said he studied it in high school in India.
Quite recently, I had a schoolteacher from the Punjab working here. She was surprised to know Indians left from Calcutta in 1838. She took the time to go to the Public Library and find books about the travel. She was intrigued, she never knew of it, never told in any form to many Indians in India. Everyday, she reviewed what she read.