China’s top court and the Ministry of Human Resources and Social Security on Thursday published guidelines and examples on what constituted as overtime work, saying they were focusing on the issue as it had attracted widespread attention recently.

While the authorities used a case involving a parcel delivery company to explain why “996” was illegal, working such hours had become a badge of honour for some Chinese companies and employees.

Silicon Valley heavyweights such as Sequoia Capital’s Mike Moritz have highlighted it as a competitive advantage the country had over the US.

But a backlash surfaced in 2019, prompting a public debate about work hours in China’s tech industry that has continued.

Last month, TikTok owner ByteDance on Friday said that it would formally end its weekend overtime policy from Aug 1, two weeks after its short-video rival Kuaishou announced a similar decision.

The court and ministry’s criticism of “996” also comes amid a wide-ranging Beijing-led regulatory crackdown on country’s technology giants that has targeted issues from monopolistic behaviour to consumer rights.