For all decision makers (Governors , Mayors, Retail stores , ect ) :

Who Recommendations:

Advice to decision makers on the use of masks for healthy people in community settings .As described above, the wide use of masks by healthy people in the community setting is not supported by current evidence and carries uncertainties and critical risks.

https://apps.who.int/iris/bitstream/handle/10665/331693/WHO-2019-nCov-IPC_Masks-2020.3-eng.pdf?sequence=1&isAllowed=y

CDC recognizes that wearing cloth face coverings may not be possible in every situation or for some people. In some situations, wearing a cloth face covering may exacerbate a physical or mental health condition, lead to a medical emergency, or introduce significant safety concerns.

This covers most people:

old people, people with asthma , anyone with low oxygen levels due to cancer or other medical problems , Children, deaf , hard of hearing , intellectual and developmental disabilities , mental health conditions, sensory sensitivities , while engaged in activities that may cause the cloth face covering to become wet , who are engaged in high intensity activities , where cloth face coverings may increase the risk of heat-related illness or cause safety concerns , those who care for or interact with a person who is hearing impaired. Anyone who is unconscious, incapacitated, or otherwise unable to remove the cloth face covering without assistance

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html#feasibility-adaptations