I can think of some
- majority dark skinned people
- spicy food
- animal life ( similar animal life in both areas)
- Jungles ( similar landscape)
- Hot tropical weather
- both africans and indians were slaved by outsiders
That little part here happened to many cultures and peoples throughout the world, in other words, it is not only confined to Africans and Indians. If you went back to ancient Rome their impressions of Northern Europeans was definitely not very delightful to say the least. If you are a student of History, where do you think the majority of the slaves came from in ancient Rome, it definitely was not India and Africa, give that a thought for once!
Interestingly, here is what the ancient Jewish writer Jospeheus said during the Roman and Jew War.
Josephus gives an account of the nation of Cush, son of Ham and grandson of Noah: "For of the four sons of Ham, time has not at all hurt the name of Cush; for the Ethiopians, over whom he reigned, are even at this day, both by themselves and by all men in Asia, called Cushites