After years of debate, the mainland has launched a pollution permit system that authorities are hailing as a major overhaul of environmental governance, the South China Morning Post reports. Under the system, environmental protection bureaus will issue emission permits to factories detailing the types and amounts of pollutants they are allowed to discharge. The policy will come into force by the end of the year for coal-fired power plants and paper-making companies, before expanding to other industries next year. However, pilot programs with the system have made little progress, and there are still big challenges. For instance, with pollution statistics from various government departments differing from each other, it would be difficult to decide the emissions limits. And the permit system did not yet cover pollutants like heavy metals or certain toxic compounds.