Why do passports only come in four colours and what is the meaning behind each?

PASSPORTS around the world correspond to one of four colors.
Travelers have either a red, blue, green, or black passport — and here’s why.

1
What does a red passport mean?
Often the color of a passport indicates which economic union a country belongs to.
The majority of the EU has a red passport, although this excludes Croatia, which is blue.
Passports of this color have “European Union” printed on the cover, accompanied by the name of the issuing EU state.
Citizens of nations with a communist history such as Slovenia, Serbia, Latvia, Romania, China, Russia, Poland and Georgia have red passports.
Countries interested in joining the EU, including Turkey, Macedonia and Albania, also switched their passports to red a few years ago.
Other countries that prefer red are Bolivia, Ecuador and Peru.
What does a blue passport mean?
The most common color is blue, which is exhibited by 84 countries.
There are 15 Caribbean countries that use this color for their passports.
The bloc of South American countries, including Brazil, Argentina and Paraguay, also uses the blue passport – the cover symbolizing the association with Mercosur, a trade union.
One of the most famous blue passports is issued to US citizens, but these were not changed to blue until 1976.
The light blue passports belong to Fiji and Tuvalu in addition to Kenya.
Great Britain has also had blue passports since leaving the EU.
What does a green passport mean?
Most Muslim countries use green passports, including examples like Morocco, Saudi Arabia and Pakistan.
Because green is considered the favorite color of the Prophet Muhammad.
The color is also considered a symbol of nature and life.
Several West African countries, including Nigeria, Niger and Segal, also have a green passport, but in their case they point out that they belong to ECOWAS (the Economic Community of West African States).
What does a black passport mean?
Black is the rarest color when it comes to passports – only seven countries issue it.


These include the African countries of Angola, Congo and Malawi, as well as Trinidad and Tobago in the Caribbean, Tajikistan and the Palestinian Territories.
Citizens of New Zealand also have a black passport – because it is the national color of the country.
https://www.the-sun.com/travel/2608024/passport-four-colours-why-red-blue/ Why do passports only come in four colours and what is the meaning behind each?