Skin colors and latitude

South indians may be darker then some tropical africans but higher latitude, also some places in central america are lower latitude then in
either Arabia or Some parts of india, but Central american indians are consideridably lighter skinned. Can that be explained by the forest cover in central america? I mean, arabia is mostly open desert. I mean,
most people in palestine or iraq are darker then Central americans for instance. Why are central americans so much lighter skinned despite the latitude?? And how are bengalis so dark skinned while their country latitude is no lower then central-northern mexico.

is that why the people arent very dark? The tree cover?