At least 23 children were killed when their school bus skidded off a mountain road into a gorge in the foothills of the Himalayas, officials have said.
Three adults were also killed in the crash, Himachal Pradesh state transport minister Govind Singh Takur told the Press Trust of India news agency.
At least a dozen people were taken to hospital.
Initial reports indicated that the bus driver was speeding and lost control at the edge of the gorge, with the bus crashing some 60 metres (200ft) to the ground below, said police officer Sunil Kumar.
The accident occurred in the Kangra Valley, about 500 kilometres (300 miles) north of New Delhi.
India's roads, particularly in the hills, have long been feared for their deep potholes, reckless drivers and, very often, a lack of guardrails. Fatal accidents are common.
"I am deeply anguished by the loss of lives," Prime Minister Narendra Modi said in a tweet.
"My prayers and solidarity are with those who lost their near and dear ones."
Rescuers were still digging through the wreckage after nightfall looking for more survivors, Mr Kumar said.