Actually, it's healthier not to wear underwear. Underwear retains moisture and a dark moist warm environment is ideal for bacterial growth. The problem is, of course, that your clothes get soiled more quickly. However, there are ways to minimize that from happening.Using a bidet is the most obvious way to cleanse yourself and minimize soiling your clothes. Underwear, like shoes, is a cultural thing. I think it's crazy to wear shoes in hot weather. It's no wonder people's feet smell. It's a wonder they don't rot. But of course if you're a professional and were to appear wearing sandals instead of shoes you'd be ostracized. So shoes may be mandatory, but underwear is not, and allowing air to circulate over your body, especially in hot weather, is definitely healthier than wearing restrictive clothing.