Starting Friday, anyone who is not wearing a protective mask on public transportation or at locations frequented by many people, such as medical facilities or pharmacies, will be fined up to 100-thousand won.

The Korea Disease Control and Prevention Agency(KDCA) said on Thursday that the one-month grace period for related revisions to the infectious disease prevention law will end on Friday.

Under Level One social distancing, wearing masks will be mandatory on public transportation, at street rallies, medical and nursing facilities and religious institutes, as well as at "high-risk for infection" sites, including call centers and logistics centers.

Recommended types of masks are "Korea Filter" government-certified masks and surgical masks. Ineffective mesh or valve-type masks are not permitted.

Businesses that fail to inform customers about mandatory mask use may face a penalty of up to one-point-five million won the first time, and up to three million won for the second offense.

Children under the age of 14 and those with health conditions that experience breathing difficulties when wearing a mask will not be subjected to the fine.