Stopped at the border, interrogated on national security grounds, laptops and mobile phones checked, held for several hours, plans for future research shattered. Many western scholars are nervous about travelling to China in the current political climate. But lately it is Chinese researchers working at US universities who are increasingly reporting interrogations – and in several cases deportations – at US airports, despite holding valid work or study visas for scientific research. Earlier this month the Chinese embassy in Washington said more than 70 students “with legal and valid materials” had been deported from the US since July 2021, with more than 10 cases since November 2023. The embassy said it had complained to the US authorities about each case. The exact number of incidents is difficult to verify, as the US Customs and Border Protection (CBP) agency does not provide detailed statistics about refusals at airports. A spokesperson said that “all international travellers attempting to enter the United States, including all US citizens, are subject to examination”. But testimonies have circulated on Chinese social …