Tayammum is a form of ritual purification in Islam that allows a person to perform prayers when water is unavailable or when using water may harm them. It involves using clean soil or dust to symbolically cleanse oneself, making it an alternative to Wudu, the regular ablution with water. To perform Tayammum, a person strikes their hands on clean earth, then wipes their face and hands. This practice is mentioned in the Quran and is especially useful for travelers or those with health issues, ensuring that they can maintain their spiritual duties even in challenging circumstances.