Quarantine "yellow jack" but this was also a name for yellow fever, which probably derives its common name from the flag, not the color of the victims (cholera ships also used a yellow flag). The plain yellow flag ("Quebec" or Q in international maritime signal flags) probably derives its letter symbol for its initial use in "quarantine", but this flag in modern times indicates the opposite—a ship that declares itself free of quarantinable disease, and requests boarding and routine port inspection. Australia has perhaps the world's strictest quarantine standards. Quarantine in northern Australia is important because of its proximity to South-east
Flag of Spain squares, or during official ceremonies. While the flag should be flown from sunrise to sunset, government offices in Spain and abroad must fly the flag on a 24-hour basis (during the night, it must be properly lit). The flags must conform to the legal standards, and cannot be soiled or damaged in any way. For mourning activities, the flag can be flown in either of the following ways. The first method, commonly known as half-masting, is performed when the flag is hoisted to the top of the flagpole, then lowered to the pole's one-third position. The other method is to