Meanwhile, on 10 October 1950, the 89th Tank Battalion was attached to the 1st Cavalry Division, increasing the armor available for the Northern Offensive. On 15 October, after moderate KPA resistance, the 7th Cavalry Regiment and Charlie Company, 70th Tank Battalion captured Namchonjam city. On 17 October, they flanked rightwards, away from the principal road (to Pyongyang), to capture Hwangju. Two days later, the 1st Cavalry Division captured Pyongyang, the North's capital city, on 19 October 1950. Kim Il Sung and his government temporarily moved its capital to Sinuiju – although as UNC forces approached, the government again moved – this time to Kanggye.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What caused the North Koreans to move their capital for the second time?
UNC forces approached