What other countries in the world do not allow dual citizenship?

Asia: Hongkong, China, Macau, China, Taiwan Province Province, China, China, Korea (with conditional recognition), Philippines, Vietnam, Cambodia, Bangladesh, Sri Lanka, Pakistan, Syria, Jordan, Lebanon, Israel, Palestine, Georgia, Turkey and Iran.

Europe: Ireland, United Kingdom, Portugal, Spain, France, Belgium, Netherlands, Germany (limited recognition), Sweden, Switzerland, Finland, Poland (acquiescence), Austria (special contribution), Hungary, Italy, Bosnia and Herzegovina (conditional recognition), Serbia, Albania, Bulgaria, Moldova, Cyprus and Malta.

North America: Greenland (Denmark), Canada, USA (acquiescence), Mexico, Barbados, Dominica, Costa Rica, Trinidad and Tobago, Jamaica, El Salvador and Guatemala.

South America: Colombia, Venezuela, Peru, Chile, Bolivia, Brazil and Argentina.

Oceania: Australia, New Zealand, Samoa, Cook Islands (New), Solomon Islands, Guam (United States), New Caledonia (France), French Polynesia, Pitcairn Island (United Kingdom), wallis islands and Futuna Islands (France), Niue (New), Tokelau (New), American Samoa and Northern Mariana Islands (United States).

Africa: Egypt, Congo * * Republic (Congo [Brazzaville]), Democratic Republic of Congo (Congo [Kinshasa]), Morocco, Cameroon, Ethiopia, Somalia, Azores (Portugal), Madeira Islands (Portugal), Eritrea, Sao Tome and Principe, Djibouti, Uganda, Gabon, Equatorial Guinea, Algeria, Tunisia.

C? te d 'Ivoire, Chad, Rwanda, South Africa, Yemen, Nigeria, Gambia, Mali, Burkina Faso, Cape Verde, Sierra Leone, Liberia, Canary Islands (West), Angola, Senegal, Seychelles, Namibia, Swaziland, Mauritius, Madagascar, C? te d 'Ivoire, Reunion (France), Saint Helena (UK), Lesotho, * * * 40.

Extended information dual nationality means that a person obtains the nationality of country A through procedures and obtains the nationality of that country again in country B. It seems that each country determines which natural persons have their own nationality according to its own nationality law, which does not conflict.

But in fact, due to the different principles of granting nationality in different countries, some people may have multiple nationalities, while others may have no nationality, thus causing nationality conflicts. In international justice, the situation that a person has two or more nationalities at the same time is called active nationality conflict. If there is a war between his two countries of nationality, no matter which side he chooses to be loyal to, it will be regarded as treason by the other side.

References:

Baidu Encyclopedia-Dual Nationality