Despite China’s recent crackdown on illegal drugs, the government faces a huge challenge.

Illegal drugs, especially meth, ketamine, and ecstasy, are now an $82 billion annual domestic business, according to the National Narcotics Control Commission. As of October, the number of addicts in China is estimated at roughly 13 million, most of them meth users, according to Liu Yuejin, the director general of the government’s anti-narcotics division.

Last year, the government’s latest operation, called “Ban drugs in hundreds of cities,” resulted in the arrest of 60,500 suspects and the seizure of more than 11 metric tons of narcotics, according to the Ministry of Public Security.

The government also targeted China’s entertainment industry, banning movies and TV shows featuring actors who have reportedly used illegal substances. In December, actor Jackie Chan’s son Jaycee was arrested for marijuana and sentenced to six months in prison.

China’s drug laws are among the harshest in the world. Those caught trafficking large amounts of drugs can face the death penalty, and police have the authority to send casual drug users to compulsory drug rehabilitation centers, which human rights groups say are little more than labor camps.

However, illegal drug use is widespread, and continues unabated. According to the New York Times, drug dealers remain a fixture in areas like Sanlitun, one of Beijing’s diplomatic districts, despite the government’s anti-drug efforts.

While heroin is preferred among rural Chinese, meth use is booming in cities, as is the new urban class with greater disposable incomes. “China is facing a grim task in curbing synthetic drugs, including "ice," which more and more of China’s drug addicts tend to use,” said Liu.

The magnitude of China’s penchant for meth is demonstrated in a study of sewage in four “megacities”—Beijing, Shanghai, Guangzhou, and Shenzen—that showed meth was “omnipresent” in the cities.