The cause of the accident was negligence and rash driving, said Superintendent of Police Arsh Verma.

He said prima facie it appeared the driver lost control of the bus and rammed it into a tree. He might have been drunk, he added.

As per the police investigation, the bus fitness certificate expired six years ago in 2018.

The school was functioning despite a holiday for Eid-ul-Fitr.

Class IV to Class X students were from G.L. Public School in Kanina. The students were on the way to the school when the bus overturned while overtaking another vehicle, police said.

The injured students were rushed to a nearby hospital.

Five children died on the spot, while two succumbed to injuries on the way to the hospital.

"Twenty children were brought here, out of which four were brought dead," Ravi Kaushik of Nihal hospital, Mahendragarh, told the media.

According to the local administration, 12 injured have been moved to a local hospital, while two were admitted to a Rohtak hospital in critical condition.