Muslim men shave their mustache as a part of their religious practice. According to a hadith, Hazrat Muhammad (Peace be upon him) said to do the opposite of pagans. Because the pagans used to have big mustaches and get their beards cleaned, so the Muslims, on the contrary, started cutting mustaches and grew beards. Another opinion suggests that mustache cutting is a part of Arab culture. Because of heavy sandy winds in that area, particles of sand got trapped in the mustache and went inside the mouth with food. That is why the custom of cutting or shortening them started. Hair removal is part of an impulse towards general purity and cleanliness in Islam, and includes the trimming of nails and the removing of armpit and pubic hair. Both men and women should remove armpit and pubic hair at least every forty days. A beard is desirable for Muslim men, and women can remove unnatural facial hair but should not reshape eyebrows for reasons of vanity.