Italian daily Corriere della Sera reports that wearing face masks will likely be made mandatory outdoors in the region of Lazio (which includes Rome) starting Thursday, December 23, 2021.

Lazio is currently a white zone, and white zones do not require wearing face masks outdoors; however, the regional government has decided to put this measure in place.

In Rome, an outdoor face-mask mandate has been in place since December 4 in some of the city's crowded shopping areas in the center and other outdoor areas where social distancing isn't possible.

https://roma.corriere.it/notizie/cronaca/21_dicembre_18/covid-lazio-mascherine-obbligatorie-all-aperto-prossima-settimana-b712e7d2-602d-11ec-9352-9ed724df04f7.shtml