Can someone who begins a voluntary fast break it?
It is preferable for someone who begins an act of worship not to break it.
Allah the Exalted has said {what means}: "and let not your [good] deeds come to nought!" [Muhammad/33].
However, if a person starts a voluntary fast (nafl) and needs to break it, they are going against what is preferable, but there is no sin upon them.
Is a person who is in a state of Janabah (major ritual impurity due to having a marital intercourse, ejaculation, menstruation, and post-delivery impurities) sinful if he/she goes about his/her daily life activities in that state i.e. without making Ghusl (ritual bath)?
It goes without saying that a Muslim should always be in a state of ritual purity so as to be able to perform prayers and recite Quran. It is from Sunnah (Prophetic tradition) that a Muslim hastens to make Ghusl from Janabah, but he/she is not sinful in case he/she delayed that provided that he/she doesn`t miss prayers. However, it is permissible for him/her to go about their daily activities while in a state of Janabah, but had better bathe in order not to miss any prayer.
Does passing wind from the anus affect ritual purity?
Ablution is nullified by the passing of wind from the anus, but washing the anus is not required as wind leaves no impurity.
Does undergoing surgery under anesthesia break the fast?
Anesthesia itself does not break the fast because anesthetic gases have no physical substance (jirm), and subcutaneous anesthesia injections do not reach the body cavity (jauf). However, this is on condition that the person is conscious at some point during the fasting hours:
● If they were awake at the beginning of the day, their fast remains valid.
● If they wake up even for a moment before sunset, their fast is also valid.
However, if the surgery involves the entry of foreign substances into the body cavity, their fast is invalidated, and they must make up for that day later.