Why are there so many Han people in Kuqa?

People of all ethnic groups in the mainland came to Kuqa and settled in Xinjiang. Kuqa county is a multi-ethnic community. After the founding of People's Republic of China (PRC), people of all ethnic groups in the mainland came to Kuqa to settle down. From the 5th century BC to the 9th century BC, there were 10 ethnic groups or tribes living in Kuqa, such as Kuqa aborigines, Qiang people, Sai people, Aryans, Han people, Xianbei people, Rouran people, Germans, Daren people, Chagas people and Tubo people. Kuqa is a county-level city under the jurisdiction of Aksu region in Xinjiang Uygur Autonomous Region, located in the middle of the southern foot of Tianshan Mountain and the northern edge of Tarim Basin. The terrain is high in the north and low in the south, and it slopes from northwest to southeast.