1. Elderly persons who cannot fast at all. There is no qaza for them either.
2. Elderly persons who can fast but with great difficulty. There is no qaza for them; however, they have to pay fidya.
Question: Who decides whether it is easy or difficulty to fast? The doctor or you? Answer: It is your judgement.
3. Temporary illness: those who cannot fast due to a temporary illness (e.g., fever, severe cold, infection, etc.). Such persons are exempted from fasting; however, they have to do qaza before next Ramadhan.
4. Long-term illness: those who cannot fast due to a long-term illness (e.g., diabetics, etc.). Such persons are exempted from fasting: there is no qaza for them either; however, they have to pay fidya for each day of fasting.
5. A pregnant or a nursing woman: if fasting would harm her or the child’s health, then she is exempted from fasting. However, she has to do qaza after pregnancy or weaning the child, and also pay fidya for each day of fasting.
Question: What if someone is overcome with thirst in summer?
Answer: If a person is overcome by extreme thirst because of fasting in summer to the extent that he cannot continue the fast, then he is allowed to drink water only to sustain himself but his fast will become invalid. He will have to do qaza later on; of course, there is no kaffarah in such a case.
Similarly, for a person who works outside and fasting in summer is not possible for him because of the heat, and he has no other comparable job, then he also is allowed to drink water only to sustain himself but his fast will become invalid. He will have to do qaza later on; of course there is no kaffarah in such a case.
In such cases, the person has to do the niyyat to fast and keep the fast as long as possible until he is not able to bear it any more – only then he can drink or eat to sustain himself.
Question: What should one do in the Europe’s northern hemisphere where days are abnormally long?
Answer: For salat, they should follow the timings of the city that is closest to them which has normal day and night.
For fasting, either travel to the southern area in Ramadhan or after Ramadhan; and if that is not possible, then he just has to pay the fidya instead of doing the fast.