 Until recently, art exhibitions deemed controversial have been routinely shut down by police, and performance artists in particular faced the threat of arrest in the early 1990s.More recently there has been greater tolerance by the Chinese government, though many internationally acclaimed artists are still restricted from media exposure at home or have exhibitions ordered closed.Leading contemporary visual artists include Ai Weiwei, Cai Guoqiang, Cai Jin, Chan Shengyao, Concept 21, Ding Yi, Fang Lijun, Fu Wenjun, He Xiangyu, Huang Yan, Huang Yong Ping, Han Yajuan, Kong Bai Ji, Li Hongbo, Li Hui, Liu Bolin, Lu Shengzhong, Ma Liuming, Qiu Deshu, Qiu Shihua, Shen Fan, Shen Shaomin, Shi Jinsong, Song Dong, Li Wei, Wang Guangyi, Wenda Gu, Xu Bing, Yang Zhichao, Zhan Wang, Zheng Lianjie, Zhang Dali, Zhang Xiaogang, Zhang Huan, Zhu Yu, Wu Shaoxiang, Ma Kelu, Ding Fang, Shang Yang, Gao Minglu and Guo Jian.