A protest against problems with the education system in the southern Chinese city of Leiyang turned violent on Sunday, with bottles, bricks, and firecrackers reportedly thrown at police by a crowd of 600 demonstrators. The police detained 46 people and said only one of them was actually the parent of a school-age child.

Reuters reports the protest began at the public schools and main city government building but then moved to the police station, where the crowd seemed to become notably more unruly. The authorities said over 30 police officers were injured in the fracas and several police vehicles were damaged.

The protesters were angry at the difficulty of getting children enrolled in the schools. “Lack of city education facilities have resulted in classes of 66 or more students. The city’s school districts are pushed to the limit: 740 classes report 66 or more students a class,” the state-run Global Times reported on Sunday.

According to the Global Times, most of the protesters were “irrelevant people,” including “a theft suspect and six with previous criminal records.” The Global Times claimed some of the bottles thrown at police were filled with gasoline, which would make them firebombs.

The Wall Street Journal quoted a Leiyang resident who watched as the protest spiraled out of control: “We tried to film it with our phones, but we decided to run. People were pushing each other and there was no place to go. It was terrifying. Later, the fighting started. A bunch of children got hurt.”

The WSJ put the protest in the context of China’s flagging economy, which turned out to be considerably less robust in some sectors than Beijing led citizens to believe:

Leiyang, which sits in coal-mining country in southern Hunan province, has seen its finances deteriorate over the past year as the coal industry went into a slump while city-backed companies racked up debts to redevelop slums and attract new businesses. In May, the city didn’t have enough money to pay civil servants, until the province dispatched emergency funds, according to the Leiyang government. After a rapid increase in debt by local governments and government-backed financing companies, Chinese leaders have for the past two years battled to contain further debt by restraining attempts to borrow more. But flagging economic growth this year has made repayment harder, forcing the government to step in and help struggling state-backed firms. In August, a financing vehicle for a paramilitary organization in far west Xinjiang missed repaying interest and principal on $73 million in bonds, sparking investor jitters about more defaults.

The parents in Leiyang were specifically angry about a plan that would force some public-school students into private schools and saddle their parents with higher tuition expenses. There were also some health concerns about the environment in recently (and incompletely) renovated private school buildings. Parents consistently filed complaints and petitions against the education plan and redoubled their efforts after children began reporting to their new schools.

Leiyang citizens might have been driven to angry protests by their government’s typically heavy-handed suppression of their grievances. Social media posts complaining about the education plan have been summarily deleted from social media. Several witnesses say the education protest was much larger than the police are admitting and did not contain all of the unsavory criminal elements and “irrelevant people” state-run media outlets are talking about.

“We can’t send out any information. As soon as we put it out, it’s immediately taken down,” one resident told the Wall Street Journal.

Chu Zhaouhui of the National Institute of Education Sciences told the South China Morning Post the protest in Leiyang was not just about education policy but grew from widespread “discontent with local governance.”

“Discontent can snowball and turn into big protests. Local authorities must improve governance from simply imposing blocks, such as deleting online postings, to … governing in accordance with the law,” added Beijing-based commentator Hu Xingdou.