Do you know why passports come in these four colours only?

If you've never had the time to think as to why passports around the world come in the limited colours that they do, allow us to enlighten you today.

Shades of red, green, blue and black are the four colours that dominate the universe of passports--and not without good reason. 

Here are the reasons for the limited colour :

Blue: Countries whose passports are blue in colour are believed to belong to the so-called 'new-world' league of nations. These nations include India, North America, South America, Australia among others.

Red: Considered to be the colour of the communist movement worldwide, red generally belongs to countries that have had a communist history or are still under its influence. China, Serbia, Latvia among others are examples.

Green: According to Business Insider, there are times faith also plays a role in the colour of a passport. Muslim nations like Saudi Arabia, Pakistan etc tend to opt for different hues of green--a colour Islam associates with Prophet Muhammad. Shades of green are also used by West African countries like Nigeria, Niger, Senegal, where the colour "indicates that they belong to ECOWAS.

Black: Black is the rarest passport colour used. One of the prominent nations that have black passports is New Zealand that chooses to be in sync with its national colour. Other nations that also have black passport are African countries like Zambia, Angola etc.