Yes and No. Various environmental protection laws are in force, such as the Water Pollution Prevention and Control Law, the Air Pollution Prevention and Control Law, the Solid Waste Pollution Prevention and Control Law, and the Noise Pollution Law. Just like with piracy, in practice, enforcement is weak. However, foreign investors should not take this as an excuse to ignore the laws, as they are under stricter scrutiny than domestic companies.
While environmental regulations are not strictly enforced at this time, they might be in the future. If they were to be enforced, this would not only lead to the closing of polluting factories, but may also raise criminal and civil liability for acts of the past. Many foreign investors voluntarily set stricter standards than those required by Chinese law. One reason is the potential for future legal liability. Another is to maintain a good public image in their home countries. Companies cannot afford the image that they relocate production to China in order to escape stricter laws in their respective home countries.