On 10, 12 and 16 June 1940, the Japanese raided Chongqing with 129, 154 and 114 bombers on these days respectively, while the Chinese I-15 and I-16 fighter squadrons engaged these attacks shooting down 13 of the raiders, perhaps more importantly, forcing bombers to miss their targets, although these disrupted flights of bombers may evade the Chinese fighters from their primary targets, and divert out to drop bombs on secondary targets, including other large population and industrial areas such as Ziliujing and Luxian. The Chinese would be dealt with a serious blow a few weeks later in July 1940 when the British yielded to Japanese diplomatic pressure and closed the Burma Road, which was China's primary lifeline for material and fuel needed in the defense of Chongqing and Chengdu.