What countries of the world are characterized by a population explosion?

The explosion was typical in the middle of the 20th century in the developing and underdeveloped countries of Africa and Asia. At this time, in these countries, through the efforts of doctors from developed countries, high-quality medical care was formed. And therefore, infant and child mortality has significantly decreased, and the survival rate has increased. However, over time, in countries that have gradually reached a high level of economic development, the birth rate has dropped significantly. Until now, Africa is at the same time a place where the population is rapidly increasing.