What should the Muslims who are prevented from fasting by the Chinese government do?

Firstly: 

We ask Allah to grant relief to our Muslim brothers in that region, and to judge between them and their enemies on the basis of truth, for He is the All-Knowing Judge. 

Our advice to them is to be patient and cling steadfastly to the faith, for tests and trials are the way of Allah in dealing with His slaves. Allah, may He be exalted, says (interpretation of the meaning):

“Do people think that they will be left alone because they say: ‘We believe,’ and will not be tested?

And We indeed tested those who were before them. And Allah will certainly make (it) known (the truth of) those who are true, and will certainly make (it) known (the falsehood of) those who are liars, (although Allah knows all that before putting them to test)”

[al-‘Ankaboot 29:2-3]. 

Secondly: 

By the grace of Allah towards His Muslim slaves, He has decreed that the one who is compelled will not be brought to account for whatever he does when he is compelled, and that whatever he does under compulsion it is all the same whether he does it or not. This includes the fasting person who is forced to eat or drink, in the sense of real compulsion in which he fears that he or his family may be harmed if he does not spoil his fast. 

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: 

If he is compelled (to break his fast), his fast is still valid and he does not have to make it up, because Allah, may He be glorified, has waived accountability in the case of one who disbelieves under compulsion, when his heart is at ease with faith. Allah, may He be exalted, says (interpretation of the meaning):

“Whoever disbelieved in Allah after his belief, except him who is forced thereto and whose heart is at rest with Faith but such as open their hearts to disbelief, on them is wrath from Allah, and theirs will be a great torment”

[an-Nahl 16:106]. 

If Allah has waived accountability for disbelieving in the case of one who is compelled to do that, then it is more likely that this is also the case with regard to lesser sins. And the Prophet (blessings and peace of Allah be upon him) said: “Verily Allah has pardoned my ummah for mistakes, forgetfulness and what they are compelled to do.” 

End quote from Majaalis Shahr Ramadan (p. 82) 

I put the question having to do with the situation of this Chinese region to our Shaykh, ‘Abd ar-Rahmaan al-Barraak (may Allah preserve him) and he said: 

They should refrain from eating and drinking whenever their watchers are not present, and they may eat when they are being watched, enough to ward off harm from themselves. And their fast is valid and they do not have to make it up, because Allah, may He be exalted, says (interpretation of the meaning):

“Whoever disbelieved in Allah after his belief, except him who is forced thereto and whose heart is at rest with Faith but such as open their hearts to disbelief, on them is wrath from Allah, and theirs will be a great torment”

[an-Nahl 16:106] 

“So keep your duty to Allah and fear Him as much as you can”

[al-Taghaabun 64:16].

End quote.