"Some children are in critical condition, so casualties could rise," said Parashuram Singh, the deputy superintendent of police in the state of Uttar Pradesh's Etah district. He told CNN that the school bus was carrying around 60 junior high school students.
An initial investigation indicates the truck was speeding in dense fog, which likely caused the accident, the deputy said.
Etah district administration had ordered all schools in the district to remain closed until January 20 due to cold weather, Satish Pal, Additional District Magistrate (ADM) of the district told CNN. He said his department was making inquiries as to why this particular school remained open.
In a tweet, Prime Minister Narendra Modi said "anguished by the tragic accident in UP's Etah district. I share the pain of the bereaved families & condole passing away of young children. I pray that those injured in the accident in Etah recover at the earliest."
India has a history of deadly road accidents. In 2015, the total number of traffic accidents increased 2.5 percent to 501,423, from 489,400 in 2014, according to the country's transport and highways ministry. Traffic-related deaths increased 4.6 percent to 146,133 in 2015, from 139,671 in 2014.
Around 83.6 percent of traffic-related deaths occurred in India's top thirteen states during 2015. The highest number of deaths had taken place in Uttar Pradesh, which reported 17,666 fatalities.
India sees an average of 1,374 traffic accidents a day -- as well as 400 deaths every day -- on roads.
This equates to almost one accident per minute and one death every four minutes on roads -- making it a bigger killer than HIV/AIDS and other diseases, according to the World Health Organization.
In a pair of particularly deadly incidents only two days apart last year in India, at least 29 people were killed -- including 17 children -- when two buses plunged into water.
During a 2013 road safety campaign, the ministry said many of these incidents were due to drunk driving, a scourge it said needed to eliminated by spreading awareness and stringent enforcement measures. It added that state governments have been requested to remove liquor shops from the side of highways.