九一一袭击 (the September 11 attacks / jiǔyīyī xíjī) were a series of four coordinated suicide attacks upon the United States on September 11, 2001.
Why it is blocked: China has been battling its own Muslim rebels, which it labels terrorists, in its Western provinces. Chinese citizens and leaders generally expressed great sympathy and condolences to the United States, but the the combination of violence, religion, and America make this a sensitive topic, regardless of China’s avowed alignment with the U.S. on The War on Terror post-9/11.
Note: Though the term was blocked when it was checked in November 2011, it has since been unblocked—a reminder that the line between sensitive and not is always shifting.
