SHANGHAI—Chinese internet platforms must clamp down on the spread of online rumors, state media outlet the People’s Daily wrote in a commentary published Thursday. The comments come amid an ongoing regulatory tightening on technology companies. The piece’s author, Zhang Tianpei, argued that curbing online rumors was especially important in the current period of preventing the spread of the coronavirus pandemic. As the coronavirus persists, “Internet rumors are even more harmful, and must be attacked strictly in accordance with the law, in order to ensure healthy operation of the internet.” The comments come as Chinese authorities steadily release new regulations and penalties addressing the tech sector. On Tuesday, China’s State Administration for Market Regulation released a sweeping set of draft rules banning practices such as fake reviews, aimed at improving fair competition online. Later, on Wednesday, China’s commerce ministry published guidelines urging video livestreamers to speak Mandarin rather than local dialects, …