Hong Kong authorities should examine the impact of social media on the city’s teenagers and explore ways to tighten control over their internet use, education and health experts have urged. Their comments came on Thursday after Australia became the first country to ban social media for children under 16, ordering 10 of the biggest platforms to bar underage users or face fines of up to A$49.5 million (US$32.9 million). Education-sector lawmaker-elect Tang Fei said he “cautiously supported” the...