BEIJING — The cabinet of China has ordered that all major industrial projects must pass a “social risk assessment” before they begin, a move aimed at curtailing the large and increasingly violent environmental protests of the last year, which forced the suspension or cancellation of chemical plants, coal-fired power plants and a giant copper smelter.

The announcement came at a news conference on Monday held in conjunction with the 18th Party Congress, at which several senior officials addressed social issues ahead of the once-in-a decade transition of power in the Chinese leadership.

“No major projects can be launched without social risk evaluations,” Zhou Shengxian, the environment minister, said at the news conference. “By doing so, I hope we can reduce the number of mass incidents in the future.”

When the protests began, they drew mostly middle-age and older Chinese who had little to lose if the police put disparaging remarks about them into the files that the government maintains on every citizen. But over the past several months, angry youths have gathered from several towns and have used social media to coordinate their activities during clashes with security forces — trends that are certain to have dismayed the country’s political leadership.