According to Transparency International, China ranks 88/177 countries/regions.
India, another large developing country, with similar population as compared to China, who also boasts as "the world's largest democracy", ranks 94/177.
Russia, another large developing democracy, ranks 127/177. Much worse than China.
Greece, a much wealthier European developed democracy with much less population to govern as compared to China, ranks 80/177 as well.
Even Italy, Europe's fourth largest economy, one of the engines of the Euro zone, an important democracy and a developed country, does not fare much better than China. She ranks 69/177.
Furthermore, China's ranking has been consistently improving if you look at historical records.
At the same time one has to bear in mind that Transparency International is a NGO based in the West. There's no way their results will be biased for China or the CPC, although the opposite case might likely be true, in fact.