Amid an ongoing surge in Christianity that developed as communism created a spiritual vacuum in people’s lives, China has launched a new crackdown, including rules introduced last month that further restrict the activities of unregistered house churches, according to a new report.

Christians in China have been repressed ever since the People’s Republic was created in 1949, with the government’s control of churches and imposition of the Communist Party’s atheistic values.

The state’s oppressive control prompted the rise of an underground house-church movement that, combined with the growth of registered churches, will make China’s Christian population the world’s largest by 2030, according to the new report by the Council on Foreign Relations.

“Tens of millions of Chinese now identify as Christians and the number has grown rapidly, posing challenges for a government that is officially atheist and wary of threats to its power,” the report says.

The growth in Christianity became noticeable shortly after the long-repressive nation was reopened to the outside world amid the reforms instituted by Deng Xiaoping after Mao Zedong’s death in 1976.

“A surge in Christian adherents can be traced from the period beginning in the early 1980s,” the report says.

The government tries to control religion by officially recognizing several faiths, including Christianity, appointing clerics and restricting activities through its State Administration for Religious Affairs.

“To register as a state-sanctioned Christian organization, religious leaders must receive training to ‘adapt’ doctrine and CCP thinking,” the report says.

A 2010 Pew Research Center report estimated that 35 million of China’s 58 million Protestants belonged to independent house churches.

Purdue University sociologist Fenggang Yang estimates there are between 93 million and 115 million Protestants in China. But other Christian organizations estimate an even higher number.

The Chinese Academy of Social Sciences and others forecast China could have 160 million Christians by 2025 and 257 million by 2032.

“Social scientists have observed the rise of a spiritual vacuum, following decades of unprecedented economic growth,” the CFR report says.

“Modern China has emerged as a wealthier and more educated society with renewed interest in religion. Consequently, experts say that as the CCP’s ideology loses public traction, Christian churches, official and unofficial, appear to be filling some of this void. Believers are not only searching for meaning in their own lives but also for the future of their country as China adapts to a rapidly changing economy and society.”

Protestantism “appeals to Chinese traditions of ritual and community,” according to French Jesuit and China scholar Benoit Vermander.

“Moreover, experts say Chinese Christians are also attracted to the faith’s sense of fellowship, comprehensive moral system, organized structure, and solidarity as part of an international movement.”

With a flood of evidence that Protestantism has become a dynamic part of China’s religious landscape, the report explains, the government, fearful of the loss of control, has increased the repression.

“For example, party officials in the eastern coastal province of Zhejiang’s city of Wenzhou, known for its large Christian population, have ordered the removal of hundreds of crosses and demolition of dozens of churches that allegedly violated construction regulations, though several had received prior approval from local officials. Moreover, Zhejiang province party officials announced that the party would enforce a ban on religious belief among party members to prevent the ‘penetration of Western hostile forces.’ Other provinces with large Christian populations, including Henan, Anhui, and Jiangsu, have undergone similar crackdowns on Christian gatherings and activities.”

CFR says that while religious leaders and practitioners “may have no intention of undermining the party, the very perception of a threat by party leaders sets the stage for possible confrontation between churches and the state.”

Among the reactions from the government has been the imposition of new religious regulations, announced last month, that are “intended to boost national security and protect against the spread of extremism and foreign infiltration,” CRF reports.

The rules include explicit bans on unregistered groups teaching about religion and increased oversight on religious gatherings and financing.

The rules specify, for example, that the state, “in accordance with the law, protects normal religious activities, actively guides religion to fit in with socialist society, and safeguards the lawful rights and interests of religious groups, religious schools, religious activity sites and religious citizens.”

They require churches to “practice the core socialist values” and ban them from creating “contradictions and conflicts.” And they require churches to assist “the people’s governments in the implementation of laws.”

The report finds that at the top level, Beijing “has signaled attempts to inject party influence into Christian ideology.”

“In August 2014, Beijing announced its bid to nationalize Christianity at a conference entitled the ‘Sinicization of Christianity.’ According to state media, SARA director Wang Zuoan said that Christian faith should first and foremost be compatible with the country’s path of socialism and that ‘the construction of Chinese Christian theology should adapt to China’s national condition and integrate with Chinese culture.’”