In 1943, Tsien was sent to India, and was responsible for organizing and importing necessary supplies into west China through India, to support the war. Because the east coastline and northeast China were already occupied by Japanese army, and the Indochina route was the only open way that Allies can deliver supplies to China. Tsien also participated in the design and manufacture of vehicles and aircraft for battle and transport uses. Tsien was ranked Colonel of the Republic of China Air Force. Tsien made contributions for Allies to the victory of the World War II East Asian battlefield.