The causes of immigrants and a nation of immigrants. The conflict in Syria is the driving force of the biggest causes of migration. But violence continues in Afghanistan and Iraq, the issue of human rights abuses in Eritrea and poverty in Kosovo is another reason people choose to contribute to a new life elsewhere. From 2015, the Eurostat data shows the top 10 countries with the most immigrants in Europe is Syria, Afghanistan, Iraq, Kosovo, Albania, Pakistan, Eritrea, Nigeria, Iran, and Ukraine.