Here are a few questions to guide you toward an answer:
Is colonization (the system under which a country "claims" land outside of its boundaries as its property) ever "fair"? Do the missionaries/colonial officials have any right to be in Nigeria in the first place?
Do the white characters respect the Ibo's right to land/property?
Do the white characters demonstrate an interest in/respect for ibo custom/religion?
Does the colonial government have the right to demand that the Ibo people follow its new laws? Does it enforce its laws fairly and for the right reasons?
What is the significance of the book's last passage? Does the District Commissioner seem to hold a "fair" view of Okonkwo and his friends?