 Complete the following phrase:  While the wartime capital of China was pushed back to Chongqing following the Fall of Wuhan, both sea and land routes for badly needed war supplies and high-octane aviation fuel were mostly cut-off, especially after the loss of Nanning in the Battle of South Guangxi and increasing threat of the Japanese invasion of French Indochina, Major Louie Yim-quns 28th Fighter Squadron, now equipped with Polikarpov I-15 fighters, has been reassigned with the 