This thread should help to begin with:
Basic Climatic Rules
also interesting:
Somatopsychical Structures in Human Races
Most Europeans in America live in areas which suit them well.
This map was made by me to show for which areas the different racial forms are primarily made for and live in today:
See also this thread about racial specialisation and climatic zones:
Racial Specialisations and Climatic Zones
Regions of origin or primary distribution:
More:
Presentation of my Racial Typology
What does a basic racial typology describe in Europe?
India is an interesting case study:
Racial Types of South Asia
Even ethnicity is there often secondary to habitats and living conditions in the racially mixed ethnic groups. So in some areas which provide a similar habitat Indo-Aryans and Dravidians are closer to each other than to related ethnolinguistic groups.