Is it illegal if you don't pay social security?

According to China's Social Insurance Law, both employers and workers are obliged to participate in social insurance. Therefore, it is illegal to not pay social security. According to the law, employers who do not pay social insurance fees in full and on time, or who do not register their laborers for social insurance, will be subject to appropriate legal sanctions. Workers are also obliged to pay social insurance fees in full and on time, or they may face fines and other penalties.