WWII was really the big catalyst for the decolonization of Africa and Asia. In Asia, much of this was a result of the power Japan exerted over the region, effectively driving out European rule. During this absence of their colonial administrators, there was plenty of room for independence movements to take root in the colonials. Post-WWII when the Europeans tried to return, they found it difficult to re-exert control.

The story is similar in Africa. During WWII, the allied powers that controlled most of the African colonies (France and Great Britain) were obviously short on the resources necessary to keep their colonies in line. This problem was worsened by the German U-Boat patrols that made trade of raw resources between the colonies and their European overlords nearly impossible, thus creating the necessity for African communities to start building up local industries to sustain themselves. The Germans also spread propaganda throughout the African colonies against their colonizers. This combination of factors facilitated growing independence movements. Post-WWII, the allies decided it would be best to allow the African colonies the independence that many of them sought, so they were granted independence as a provision of the Atlantic Charter.