As I read it, it's not anything particular you can pick. The whole book paints portrait of society and life in the area. Interactions of characters are there to show and illustrate those discourses and atmosphere of the society. And people's places in social structures.

For example. In the first part, I felt the locals were main focus and how these foreign professors people can justify to themselves going with the flow and exploit people. As societal structures make it possible.