ancestry to various degree. I got it from a conversation when a chinese friend(a grad student in political science) questioned a bangali why did he has the family name Khan.
Bangal has its own ancient civilisation.Remember I mentioned there's certain amount of animosity between bengalis and,say,lighter skin punjabi. The punjabis don't like the darkie bengalis and the bengalis claim they're culturally superior to the punjabis.
Australian natives originated from india:
http://www.bbc.com/news/science-environment-21016700
As I said humans 15000 years ago all had dark skin and those in N europe and N asia had their skin bleached during the last ice age. Whenever I met an african in HK, I'll tell him or her chinese are pale skin africans. The hindus insistence they're 'aryans' (whenever they made that claim,they might post the pic of a hindus of fairer skin)basically due to:
1)Brahmin dominated caste system
2)It happens that europeans have been overall the most economically and technically accomplished race in the past few centuries and the hindus want to rub some shines off them
Little other than deep rooted inferiority complex.
(BTW, in southern china, one might occassionally spot darker skin chinese or chinese who look like pinoys. I bet they're recent descendents of more remote villlages or some minority tribes of australoid origin. )