How are halos used in religious art to symbolize the divine presence or holiness of the depicted figures?

Halos are used in religious art to symbolize the divine presence or holiness of depicted figures. The circular shape of the halo represents the eternal and infinite nature of the divine, while the radiant light emanating from it signifies the spiritual enlightenment and purity of the figure. This visual symbol helps viewers identify the depicted figures as sacred or divine beings.