Because of the epidemic in Yancheng, Jiangsu, students have to be quarantined at their own expense when they return home?

Yes, you need to pay for isolation at home. According to relevant information: Whether you are returning from abroad or traveling between domestic cities, you must bear the costs of being quarantined due to the epidemic (nucleic acid testing costs, accommodation fees, meals, transportation fees, etc.). This situation requires Own responsibility. If the government mandates quarantine, the cost of quarantine in a hotel will be borne by the government.