The incident happened at around 7:08 a.m., when Bus No. 301 caught fire in front of a furniture store in Helan County in the regional capital of Yinchuan. The site has been cordoned off, and the injured are receiving treatment in hospitals.
According to the police, Ma owns three cars. Police in Ningxia localities are checking for the suspect and the car plate numbers on various roads and highway entrances and exits and will alert the regional department if any leads are found.
The bus, which belongs to state-owned Yinchuan Public Transport Co. Ltd., was bound for the Yinchuan Railway Station.
Pictures on microblog Sina Weibo show the entire bus engulfed by fire and smoke.
Further investigation is under way.