Exhaust gasses from a coal factory are likely to blame for the hospitalization of 64 people on Saturday, say authorities in Xizhuang, a town in Shaanxi province.

According to an official statement, four people remained in hospital by Sunday afternoon.

Though the cause of the mass illness is not yet confirmed, officials suspect a nearby factory whose waste gasses left 45 people with symptoms including coughing and dizziness in 2014. Then, a storm had knocked out a system that disperses exhaust fumes. (Image: VCG)