China's pollution levy is one of the few economic instruments with a long, documented history of application in a developing country. Article 18 of China's Environmental Protection Law specifies that "in cases where the discharge of pollutants exceeds the limit set by the state, a compensation fee shall be charged according to the quantities and concentration of the pollutants released". At present, approximately 300,000 factories are monitored and potentially subject to levy collections by national, provincial and local regulators.