In Jain cosmology, the manushya loka is the middle world where humans live. The main kshetras of human existence are:

1. Bharat Kshetra
2. Airavat Kshetra
3. Mahavideh Kshetra

These are the principal karmabhumi areas, where spiritual practice, karma bondage, and liberation are possible.

There are also akarmabhumi regions in the human world, where life is more सुखमय and less active in karmic effort, but the main human spiritual fields are the three kshetras above.

If you want, I can also explain the 15 karmabhumis and 30 akarmabhumis in simple Jain terms.