Even though almost all romanizations in mainland China today are in Pinyin, there are still some exceptions. For example, the name of the province Shaanxi is written in GR rather than in Pinyin, which would be Shǎnxī with tone markers, because there is already another province named Shanxi, which is written as Shānxī with tones. If the Pinyin names were to be written without tone markers (which they often are in everyday Pinyin), they should both be spelled Shanxi. Therefore they would be impossible to tell apart using just Pinyin without tones. Therefore, an exception has been made in this case. 