TIME
Sudan’s flag is as similar to South Sudan’s new one as it is different. Green represents natural resources in one, but for Islamic prosperity and agriculture in the other. Black represents black Africanness in one, but the Mahdist revolution in the other. Red represents blood shed for independence in one, but for martyrdom in the Sudan and in the Arab world in the other. white unites the two countries: both stand for some form of peace attained.
REPUBLIC OF SOUTH SUDAN FLAG, RAISED JULY 9, 2011

Initially used by SPLM/A during the liberation Struggle. The Flag was adopted as a National Flag of the New Republic of South Sudan by all Political parties, the Government of South Sudan Cabinet and the South Sudan Legislative Assembly.
Black stand for the Black Africans
White represents the peace attained after many years of the liberation struggle.
Green symbolizes the country’s natural resources
Blue reflects the waters of the River Nile- a source of life for the new country.
The yellow Star guides the country and its citizens
SUDAN NATIONAL FLAG, lowered on July 9, 2011

GREEN: represents and symbolizes Islamic Prosperity and agriculture
RED: The red colour stands for the struggles and for martyrs in the Sudan and the great Arab Land
WHITE: The white colour stands for peace, optimism, light and love
BLACK: The black symbolizes the Sudan and the Mahadist’s revolution during which a black flag was used.
CONTEXT
The flag of the Republic of South Sudan has been hoisted at the African Union Headquarters in Addis, following admission to the continental body.
RSS is AU’s 54th member.
The Addis Ababa-headquartered organisation Wednesday said it had accepted an official request for membership from the Southern Sudan government.
The membership is in line with the AU’s constitutive act, the club said in a statement, adding that the decision had been circulated to all member states and international organisations.
An official welcoming ceremony will be held as soon as possible in consultation with Juba, it further said. South Sudan’s flag has already been hoisted at the AU’s compound to recognise the newly-born member state.
Southern Sudan declared independence on July 9 following a week-long referendum in January that overwhelmingly voted for secession from the North.