Advance Army Air Forces echelons arrived in India in December 1943 to organize the building of airfields in India and China. Thousands of Indians labored to construct four permanent bases in eastern India around Kharagpur. As well as construction or modification of airfields in Bengal, a fuel pipeline to Calcutta and expansion of the port there was proposed. Meanwhile, to the northeast, across the Himalayan mountains, about 350,000 Chinese workers toiled to build four staging bases in western China near Chengtu (where Chennault had already developed airfields) and new airfields near Kunming.