Those riding public transportation in South Korea are required to have their masks on, as part of a new measure, effective Tuesday, to prevent community spread of the novel coronavirus, health authorities said Monday.

The Central Disaster Management Headquarters said the face-covering mandate affects both passengers and staff on buses, taxis and subways. Masks are deemed critical in curbing COVID-19 here.

Airline passengers on board all domestic and international flights will be instructed to wear masks, starting Wednesday, health authorities added.

“With the weather getting warmer, there have been cases showing a growing complacency over wearing masks among some passengers and staff in buses and cabs,” Yoon Tae-ho, a senior health official, said at a daily briefing.

Transportation operators and staff who refuse entry of passengers without masks will be exempt from administrative punishments such as penalties and business suspensions, Yoon added.

The measure, however, is not legally binding and there is no way to stop mask-less passengers from boarding the vehicle even after denying them entry.

As of Sunday, there were 21 virus infected patients in the public transport industry, health authorities said.

By Kim Bo-gyung (lisakim425@heraldcorp.com)