Two issues continued to create grievance through the 1930s and 1940s. The colonial government strictly regulated the buying and processing of cash crops, setting prices and reserving the role of intermediary for Asians, who were thought to be more efficient. The British and Asians firmly repelled African attempts to break into cotton ginning. In addition, on the Asian-owned sugar plantations established in the 1920s, labour for sugar-cane and other cash crops was increasingly provided by migrants from peripheral areas of Uganda and even from outside Uganda.