Achebe has gone on to write about how the British influence in Nigeria has caused the corruption there since.  This is an accurate representation of Nigeria, because the British came into the land and imposed their religion, and their governing system on the Nigerian people, causing them to push back their own beliefs and customs.  Because of this, some Nigerians resist and rebel, while others conform, causing tensions between groups of people that weren't so apparent before the British colonialism.  When the British brought their government into Nigeria, the Nigerians were forced to accept that government, or else they would feel the punishment of it, so this is where life structure started to disassemble in the area.  I really do believe that the corruption in Nigeria was, at least in part, caused by the British colonialism in the late 1800's.