In what part of the world is asthma least prevalent and why?

The correct answer is Africa and also India .

In South Africa, for instance, although the prevalence of asthma has been increasing over the past few decades, it is still relatively low compared to many other parts of the world. Several factors contribute to the lower prevalence of asthma in Africa and India, including:

Lifestyle and environmental factors: Traditional African and Indian diets are typically high in fruits, vegetables, and whole grains, and low in processed foods, which may help to reduce the risk of developing asthma. Additionally, many African and Indian communities have a strong cultural emphasis on outdoor activities, which can help to improve respiratory health.

Genetic factors: Some studies have suggested that certain genetic variations may be associated with a lower risk of developing asthma. These variations are more common in African and Indian populations than in other parts of the world.

Hygiene hypothesis: The hygiene hypothesis suggests that early exposure to a variety of microbes and allergens can help to train the immune system and reduce the risk of developing allergies and asthma. Many African and Indian communities live in rural areas and have higher levels of exposure to a diverse range of microbes, which may contribute to the lower prevalence of asthma in these regions.