China has adopted a sweeping ethnic unity law that critics say tightens assimilation and weakens minority rights. On Thursday, legislators at the National People’s Congress approved it. A delegate says it aims to build a shared national identity across every group and workplace. Scholars say the law undercuts promised autonomy in China’s constitution and ethnic autonomy rules. It mandates Mandarin as the primary teaching language in compulsory education. Experts said language about mixing communities are also concerning and say it could lead to the break up of minority neighborhoods. The law also opens penalties for actions abroad that Beijing says harm ethnic unity.