The persecution of Christians in China is the worst it has been for more than a decade, with at least 50 million people expected to experience some form of repression this year as the government tightens its controls over religious worship, according to a global monitoring body.

The crackdown on religion in China is part of a pattern of increasing Christian persecution across Asia over the past five years, Open Doors said in its 2019 World Watch List, which ranks 50 countries. One in three Christians face high levels of persecution in Asia, with India entering the top 10 for the first time.

Open Doors estimates that 245 million Christians worldwide face high levels of persecution this year, up from 215 million last year.

The publication of its annual league table comes three weeks after Jeremy Hunt, the UK foreign secretary, ordered an independent, global review of the persecution of Christians of all nationalities. The review will make recommendations on the practical steps the UK government can take to support those under threat.

North Korea tops the World Watch List for the 18th year in a row, with 10 other countries categorised as having “extreme” levels of persecution. Countries that have moved up more than 10 places in the list in the past year include China, Algeria, Central African Republic, Mali and Mauritania.

China has risen from no 43 on last year’s list to 27 in 2019. Henrietta Blyth, the chief executive of Open Doors UK and Ireland, said: “In China, our figures indicate persecution is the worst it’s been in more than a decade – alarmingly, some church leaders are saying it’s the worst since the Cultural Revolution ended in 1976.”

There are an estimated 93 million to 115 million Protestants in China and about 10 million to 12 million Catholics. Most belong to unregistered churches. If the rate of growth continues, China is expected to have the world’s largest Christian population by 2030.

In the past year, the Chinese government has tightened its control on religious worship, shutting down hundreds of unofficial churches, detaining pastors and worshippers, removing crosses from buildings, banning the online sale of bibles and increasing the surveillance of congregations. Last month, the celebration of Christmas was banned in some schools and cities.

“There is a very strong control agenda combined with a new era of digital surveillance,” said Ronald Boyd-Macmillan, the head of strategy and research at Open Doors.

He said persecution was being driven by three factors: the strong ideological leadership of China’s president, Xi Jinping, the government’s unease over the growth of Christianity, and the harnessing of technology as a repressive tool.

In September, the Vatican signed a provisional deal with Beijing on the appointment of Catholic bishops, aimed at a rapprochement in diplomatic relations. However, critics denounced it as a betrayal, with Cardinal Joseph Zen, the former archbishop of Hong Kong, saying the consequences would be “tragic and long lasting, not only for the church in China but for the whole church because it damages credibility”.

India, the world’s largest democracy, rose to 10th place on the list, having been 28th five years ago. Open Doors said ultra-nationalism was behind the increase in violent attacks by Hindu extremists on Christians and churches.

“It’s shocking that India – the country which taught the world the way of ‘non-violence’ – now sits alongside the likes of Iran on our World Watch List. For many Christians in India, daily life is now full of fear – totally different from just four or five years ago,” Blyth said.

The report also highlights the rise in gender-specific persecution, saying Christian women are subjected to sexual violence, rape and forced marriage in the top five countries on the list.

Speaking ahead of the launch of the report on Wednesday, Hunt said: “People of all faiths and none should have the freedom to believe what they choose, but that is clearly not the case across too much of the world … Faith isn’t a crime, believers shouldn’t be treated as criminals, and the UK must fight for that to be the case across the world.”