Is it obligatory for Muslims in China to emigrate, considering the difficult religious and social conditions imposed upon them, and will a طالب علم شرعي (religious knowledge seeker) be held accountable if he emigrates and does not remain for da'wah (Islamic propagation) after acquiring knowledge?

Emigration from disbelieving lands to Islamic lands varies in its ruling depending on the circumstances; it can be obligatory or recommended. Emigration becomes obligatory for whoever is unable to practice the rituals of their religion or fears being tempted away from their religion. There is no harm for one who possesses beneficial knowledge and firm faith to remain for the purpose of da'wah (inviting to Islam), provided they are secure concerning themselves and their family.