When you are born, you can acquire citizenship via the following rules: 'right of blood' (ius sanguinis) and 'right of soil' (ius soli).
The ‘right of blood’ says that by birth, you acquire citizenship of your parents’ country.
In the case of ‘the right of soil’, you acquire citizenship of the country of your birth, regardless of the citizenship of your parents. What does it really mean? If you were born in Poland, you automatically acquire Polish citizenship.
Each country adapts appropriate laws that suit their interests and traditions
Generally speaking, emigration countries apply the ‘right of blood’ to preserve the bonds of nationality and citizenship.On the other hand, immigration countries, which aim for the fastest possible assimilation, adopt ‘the right of soil’. That means whoever was born on their land was automatically granted citizenship of the country.
Poland follows ‘right of blood’ when it comes to acquiring and passing Polish citizenship to next generations. What that means is that by law and regardless of whether you were born in Poland or abroad, if at least one of your parents is a Polish citizen (or of Polish descent), you acquire Polish citizenship. In simple words, if let’s say your great-grandfather was Polish, he would pass his citizenship to his child (your grandparent) and further on to your parent. Following ‘right of blood’ makes you Polish too.
Polish citizenship law also applies to those born in countries with the ‘right of soil’ (ius soli). In other words, if you were born in the US to a Polish parent (or of Polish descent), despite acquiring US citizenship, you will also hold Polish citizenship.
Germany, Poland, France, Ukraine, Australia grant citizenship through ‘right of blood’.
When it comes to ‘right of soil’, it applies in such countries as Argentina, Brazil, Chile, Jamaica, Canada, Colombia, Mexico, Pakistan, Peru, the United States, Tanzania, Uruguay, Venezuela, and Barbados.