An interesting fact

People of Indian origin made it to the top news this week. I did some research and let me share some other interesting facts with you. 3 out of 9 Nobel prize winners came from the Tamil Brahmins community in Tamil Nadu, the population totaling only 42.50 lakh (4 250 000) (a tiny amount compared to total India's population) List of Indian Nobel laureates - Wikipedia
They are:
C. V. Raman (physics, 1930);
Subrahmanyan Chandrasekar (physics, 1983);
Venkatraman Ramakrishnan (chemistry, 2009).

Who else are the notable members of this community, you will be surprised!
Indra Nooyi, Former CEO of PepsiCo
Sundar Pichai, CEO of Alphabet Inc.
Srinivasa Ramanujan, Indian mathematician
S. R. Srinivasa Varadhan, mathematician and Abel Prize laureate
Viswanathan Anand, Indian Chess Grandmaster
Shyamala Gopalan, biomedical scientist, Mother of U.S. Vice President Kamala Harris

What is the reason for such a phenomenon?