Section 24. The deputy director may grant without fee, on proof of identity, a special state license to act as hawker or peddler, subject otherwise to this chapter, to a World War I or II or Korean or Vietnam veteran, as defined in clause Forty-third of section seven of chapter four, who has a service-connected disability as recognized by the United States government; and to any blind person resident in the commonwealth and approved by the commissioner of the blind; provided, that no license under this section shall authorize the holder thereof to act as hawker or peddler on any public street or sidewalk in any city or town unless and until he shall have received written authority so to do from the chief of police or other official having charge of the police therein.