China has passed a controversial national-security law that gives Beijing the power to stamp out opposition in Hong Kong after the territory was rocked by pro-democracy protests last year. The Chinese legislature approved the law on June 30—a day before the July 1 anniversary of Hong Kong’s handover from Britain to China in 1997, which is often marked by pro-democracy demonstrations. The exact wording of the law has not been released by Beijing, but BBC News reports that it will criminalize secession, subversion, and collusion with foreign forces. It could, therefore, be used to crackdown on protests and freedom of speech. Tam Yiu-chung, Hong Kong’s representative to the top legislative body in China, warned: “Those who have stirred up trouble and broken this type of law in the past will hopefully watch themselves in the future.” The Demosisto pro-democracy group, led by Hong Kong’s most prominent activist, Joshua Wong, said it would now halt operations, adding that it would be “unsustainable” to carry on under the new law.