The woman in the ambulance was recuperating post-surgery after an accident and was being taken home at the time of the mishap; police book bus driver for rash and negligent driving
source https://www.thehindu.com/news/national/kerala/private-bus-rams-ambulance-container-lorry-injuring-patient-passengers-in-kochi/article68702802.ece
source https://www.thehindu.com/news/national/kerala/private-bus-rams-ambulance-container-lorry-injuring-patient-passengers-in-kochi/article68702802.ece