The primary reason the 64th Troop Carrier Group, plus one squadron of the 62nd Troop Carrier Group, went to India was to aid in the relief of about 170,000 British troops who were surrounded by the Japanese in the Imphal Valley (See town of Imphal just below the info box, which reads: "This road cleared of Japs.")

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WWII Era Map of CBI Area
With a little imagination one can see a relatively flat area around the town of lmphal (in a valley surrounded by mountains).
If the Japanese had captured these troops, there was little to stop them from a sweep into Calcutta and other vital points in India.
At the town of Sylhet, west of Imphal, where there was a large airfield. It was from here that about three squadrons flew most of their supplies into Imphal. These units were based off the map, about one-and-one-half hours to the southwest of Sylhet.
During this operation the Japanese struck Imphal nearly every morning at 8:20 a.m. So, if we left before 8:00 a.m. or arrived after 8:45 a.m., the chance of an encounter was slight. (They had about twenty minutes of fuel that could be used to hang around Imphal.)

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Airfields in Upper Assam, India |