Heretofore the repression has been in Xinjiang Province, China's northwestern-most province. The repression has focused on the Uighur people group, who apparently have not adapted with Han Chinese culture. While Islam is a factor, distance from the more populous areas of China - the cultural heartland - is a greater factor. Other people groups who are also majority Muslim in other provinces have adapted successfully, and have been tolerated. For example, Xining, the capital of Qinghai Province - a province that borders Xinjiang on the east - has a large, centuries old, mosque that is in full use, as well as several other mosques.
That said, I saw a news report a week or two ago that Muslims in Gansu Province, another province that borders Xinjiang on the east, are experiencing repression, and not among the Uighur people group.
