Oppressive measures such as the “one-child” policy — and Beijing’s refusal to take back most people who are deported from the U.S. — have left the U.S. with more asylum seekers from China than any other nation.

Expand chart Data: Department of Homeland Security. Affirmative asylum includes people who apply right away, defensive asylum includes people who were already in deportation proceedings. Chart: Andrew Witherspoon/Axios

Why it matters: This has long been a point of tension between the two world powers. Beijing blames the U.S. for enticing Chinese nationals to leave by granting them asylum, but the U.S. blames China for what it perceives to be oppressive policies and for making it difficult to deport people back to China.

By the numbers:

80% of Chinese defensive asylum claims — those made while already in deportation proceedings — were approved between 2012 and 2017, compared to 21% for Salvadorans and 12% for Mexicans, according to data collected from immigration courts by the Transactional Records Access Clearinghouse at Syracuse University.

And affirmative asylum, which can be claimed by an immigrant as soon as they arrive in the U.S., is generally easier to win.

China is a big country, but India — which is almost as populous and sends as many immigrants to the U.S. — has far fewer who claim asylum.

What drives Chinese nationals to the U.S., and leads to their high asylum approval rates:

The “one-child” policy, which went into effect in 1980 and spurred widespread infanticide and forced abortions, was a compelling argument for claiming asylum. The recent decline in asylum seekers coincides with the relaxation of the policy starting in 2013. The policy officially ended in 2016. Political dissidents came to the U.S. from China in huge numbers after the Tianamen Square protests in 1989. The nearly 80,000 Chinese nationals Religious dissidents include Chinese nationals who practice Islam and Christianity — as well as those who practice Falun Gong, a pseudo-Buddhist faith, Sun says.

Even if asylum is denied, many Chinese immigrants find themselves stuck in the U.S. with deportation orders as Beijing often refuses to allow their return, Doris Meissner, a former Immigration and Naturalization Service commissioner and senior fellow at Migration Policy Institute, tells Axios.

In 2017, just 525 Chinese nationals were successfully deported —up from 398 the year before. Meissner says that under the Trump administration, “DHS and ICE are under strong pressure to increase the pressure on these countries, including China, and get higher numbers of returns.”

The bottom line: There are sweeping actions the U.S. can take against countries that don't readily accept deportees — such as Cuba, Iran, Morocco and Vietnam — like refusing to issue visas to their citizens. But in China’s case, this strategy doesn’t make practical or political sense, Meissner says. China is a key economic partner, and it’s just too big.

Go deeper: Trump inherited a surge of Central Americans seeking asylum