The gas leakage might have happened due to the containers not being properly sealed after being checked.
The chemical gas leak from the Tughlakabad container depot that affected over 450 girl students might have happened due to the containers not being sealed properly.
Police, however, said they are yet to ascertain the point where the carelessness occurred that led to the incident.
It is suspected that yesterday's leakage might have happened due to the containers not being properly sealed after being checked.
Meanwhile, some students are still undergoing treatment at the hospitals. A few teachers and locals were also affected.
As many as 16 girls are still admitted in Humdard Institute, 11 are admitted in ESIC, two are in Batra Hospital while one is in Apollo Hospital. Three have been referred to Safdarjang Hospital, doctors said.
Police said a team of National Disaster Response Force (NDRF) and other agencies reached Sonipat in Haryana today to check the container and the initial cause of the leakage.
Police are in the process of collecting documents from the various parties involved to identify the point at which the lapse occurred.
The NDRF had said a truck carrying 80 cans of chloromethyl pyridine had left the Tughlakabad Depot on its way to Sonepat at 3.30 am yesterday.
The Delhi government, which ordered a magisterial probe into the incident, has issued a show cause notice to the depot authorities.
Police had registered an FIR in the matter under various sections of IPC and the Environment (Protection) Act against unidentified persons.
The southeast district administration also issued a show cause notice to the Customs department and the Container Corporation Of India Ltd (CONCOR), the custodian of the depot.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)