Valid reasons for not keeping a fast:
These are the valid reasons for not keeping a fast:
Journey, whether it is for a valid reason or invalid reason, whether it is taxing (like by foot, etc.) or comfortable (like a train/plane). However in a comfortable mode of travel, it is better to fast. Here travel means travel as per the Shariah, which is equivalent to a 3-day journey. If the journey starts after the Niyyah of the fast was made, then completing the fast is compulsory. If it is broken, then Kaffara will not become Wajib, only Qaza. If someone breaks the fast and starts the journey after breaking the fast, then Qaza and Kaffara both become Wajib.
If a sick person feels that by fasting, the disease will worsen or the person will regain his/her health after a long time. This the sick person knows by his/her own experience or by some sign or by a Muslim physician, who does not openly break rules of Islam. If a healthy person thinks that by fasting, he/she will fall ill, then they are also included in the same rule.
Pregnancy, if the lady thinks that she or her child will be at risk by fasting.
A lady who is nursing, regardless of whether as a mother or a nurse, if she thinks that she or the child will be at risk.
If someone cannot bear hunger/thirst and there is a danger of their death.
Old age, in which weakness increases day by day and there is no strength to fast.
Force, i.e. someone is forcing one to not fast, provided there is extreme danger, like death.
Situations in which one might break a fast:
If the fasting person suddenly falls, for e.g. has a sudden fever or headache, stomachache or a snake/scorpion bites that person or a pregnant lady faces something, which makes it risky for her or her child or if the fasting person faces such hunger or thirst that there is danger of death or if someone forces the fasting person to break a fast, provided there is a real danger of death or extreme loss. In all these cases, breaking the fast is allowed.
In all the above cases, Qaza of the fasts is Wajib, excepting for old age, where for missed fasts 1 Sadqa Fitr for each fast has to be given or a needy person can be fed twice a day.