Diversity visas are intended to provide an immigration opportunity for persons from countries other than the countries that send large numbers of immigrants to the United States.
The law states that no diversity visas shall be provided for high admission countries. Those are countries from which during the previous 5 years there were more than 50,000 immigrants in the Family-Sponsored and Employment-Based visa categories.
Each year, US Citizenship and Immigration Services (UCIS) adds the family and employment immigrant admission figures for the previous 5 years to identify the countries that must be excluded from the annual Green Card Lottery. Because there is a separate determination made before each Visa Lotter application period, the list of countries that do not qualify can change from one year to the next.
Under certain circumstances you could still participate even if you were born in a country does not qualify.