Hong Kong police say 10 people were arrested on July 1, 2020, under the city’s new national security law. It was the first time the police force exercised their new powers under the contentious legislation enacted the previous day by Chinese mainland authorities. The 10 were among about 370 people detained mainly for taking part in illegal assemblies, disorderly conduct and possession of offensive weapons. Despite the new risk of prosecution, thousands of anti-government protesters took to the…