How did the settlers in the book contribute to the death of Okonkwo?

The changes of his son was a heavy blow for okonkwo. Then the people's and their subjugation rushes him to baffle. His belief that a man should master his own fate. His faith in his clan shattered. On the other side okonkwo's suicide is the tragedy of people's subjugation. His suicide violates the tradition. His inward emotions are complex. His manly nature brings a conflict with the unmanly ideas of the environment. His outrageous nature though justified it does not provide him any way of stopping the whites. Okonkwo worries about, suppose when he died all his male children decided to follow Nwoye's steps and about their ancestors. This shows African writing had the power of emotional response from the readers.

The white European colonists gradually undermine the traditional Igbo culture and eventually take control of Umuofia and the surrounding tribes. Okonkwo is portrayed as a callous, obdurate man, who supports traditional Igbo customs and is completely opposed to the spread of European culture in the region. During Okonkwo's exile, the Europeans establish schools, stores, churches, and a bureaucracy in the region that undermines the authority of Umuofia's elders. When Okonkwo returns to his village after seven years, he sees the changes made in his community and responds by destroying a Christian church. Okonkwo and his fellow elders are then arrested, tortured, and disrespected by the European officials, which further antagonizes Okonkwo. Eventually, Okonkwo cannot contain his rage and negative feelings towards the Europeans and ends up decapitating a white messenger after learning that the tribe will not fight against the colonists. Rather than suffer punishment at the hands of the white oppressors, Okonkwo tragically commits suicide by hanging himself from a tree in his compound.