When bathing is required. The Qur’an calls on Muslims to keep their clothing clean and pure. The Qur’an refers to a true house of worship as a place in which are found men who love to purify themselves; Allah (God) loves those who purify themselves. If a person is in a state of sexual defilement, it is necessary to wash before prayer. However, if a person is sick or travelling or coming out from relieving himself or has touched a woman and cannot find water, then rubbing the hands and face with pure earth is sufficient.
Humbistri Karny K Bad Ghusal Kab Tak Karna Chahiye.