HONG KONG—Hong Kong authorities ousted an opposition legislator from his seat Aug. 26 after finding him to be insufficiently loyal amid Beijing’s tightening grip on the semi-autonomous city. Cheng Chung-tai of the populist Civic Party was disqualified from the legislature after he “failed to fulfil the legal requirements and conditions on upholding the Basic Law and bearing allegiance” to Hong Kong, the government said in a statement. The Basic Law is Hong Kong’s mini-constitution. He was one of two remaining opposition lawmakers in the legislature, after the pro-democracy camp of legislators resigned en masse last year following the disqualification of four of their colleagues. Hong Kong’s chief secretary, John Lee, said in a news conference that Cheng was disqualified after an opinion was sought from the territory’s national security committee, which said Cheng had failed to comply with the requirements of being a legislator. The committee was set up last …