The air quality around Chinese cities is worsening because of coal fired plants and increasing demand for energy, and because of exhaust from automobiles filling the highways. The air quality around Beijing violated the WHO standards more than 80% of the time during the fourth quarter 2008 period. China's Ministry of Environmental Protection says in a report that more than 25% of China's rivers, lakes and streams are too polluted to be used for drinking water. And acid rain is a problem in 200 of 440 cities it has monitored. Efforts to control the exhaust pollution from cars by putting driving restrictions in Beijing are not as effective. One report says that even after 20% of private cars are taken off the road each weekday, the 250,000 new cars that were added to Beijing's streets in the Jan-April 2010 period, have left things as bad as they were before.