As Japan returns to work from coronavirus restrictions, its notoriously crowded trains--almost a symbol of its celebrated work ethic--are raising fears about a resurgence of infections.

Authorities in Tokyo had hoped to solve the problem of crowded commuting with staggered hours and remote working but the trains appeared almost back to normal on Thursday, days after the lifting of a coronavirus emergency.

Health experts and politicians have blamed night spots and concert venues, known as live houses, for cultivating clusters of infection and have advised them to stay closed.

But while no coronavirus cases have been linked to trains, many Tokyo residents say they are just as packed as any nightclub.

“It’s such a contradiction that crowded trains are OK but live houses still can’t open,” said Twitter user Rimiken.

“Crowded trains are like a music festival. They’re a festival mosh pit.”

Tokyo recorded 34 new infections on Tuesday, the highest daily increase since early May.

The Tokyo Metro subway is taking steps to prevent infections with open carriage windows and the disinfecting of ticket machines, spokesman Hisao Asano said.

But it has no plan to limit passenger numbers or insist on spacing, he said.

“Given the various needs of our customers, we’re not thinking about such a blanket restriction,” Asano said.

But a study by one of Japan’s top research institutes indicated it may have to. The Riken Center for Computational Science found that even with open windows, the air flow concentrated above passengers’ heads on crowded trains.

Government infection expert Shigeru Omi said crowded trains could no longer be an everyday reality.

“The train is the symbol of Japanese workaholic society,” Omi told reporters. “This is an opportunity for Japan to address this issue of overcrowded trains by, first of all, staggered working hours and remote work.”