Why China is investigating Didi and other big Chinese tech firms

Chinese regulators have clamped down on the country's largest ride-hailing app, Didi Global, days after its shares began trading in New York. Authorities told Didi to stop new registrations and ordered its app removed from China's app stores pending a cybersecurity review. 

The government said it was acting to prevent security risks and protect the public interest. Didi is the latest company to face intensified scrutiny in a crackdown on some of China's biggest technology giants.