While I’ve only visited a few cities in mainland China, the food delivery drivers that I have see have all worn open-faced helmets like this:
As to why, apart from it being generally anti-social - it’s mainly because it’s a massive security issue, as the individual in question cannot be identified in the event of assault, theft or order crimes.
Alcoholicorn@mander.xyz 3 days ago
Did you come over in winter? I am in Urumqi and its quite common to see open-faced helmet with a scarf/necktube/jacket pulled over the mouth/nose, I also saw it in Korea.
You have cameras which presumably can see their bike liscense.
Then again, masking in public due to illness/air pollution is common over here, it would be weird to ban just delivery drivers from covering their faces.