( CNN ) -- Feeding India 's hungry school children is an undertaking unparalleled anywhere -- the $ 22 billion-a-year scheme provides a hot meal to an estimated 120 million students every school day . Reetika Khera , an economist at the Indian Institute of Technology Delhi who has studied the scheme , credits the `` very ambitious , very large and very popular '' program with having a huge impact on student enrollment and attendance in a country in which , according to official government figures , nearly half of all children are malnourished . But the tragic deaths of at least 22 children and hospitalization of 24 more after eating a school meal in India 's northeastern Bihar state highlight the failings of the program to provide healthy -- or even safe -- meals , in some parts of the country where governance , accountability and poverty remain entrenched issues . Read more : Principal on the run , children recover . The students became ill immediately after eating the meal of rice and potatoes in the village of Dahrmasati Gandawan on Tuesday . The circumstances leading up to the contamination , which has provoked violent protests in the region , remain murky , with the school 's principal and her husband having absconded and currently being sought by authorities , area police chief Sujit Kumar told CNN . But Bihar state Education Minister P.K . Shahi has said the children were poisoned by an insecticide that was in the food . Officials believe the substance involved was organophosphorus , a chemical that the U.S. Center for Disease Control and Prevention says is commonly used in agriculture . Khera said the national school meal program had its origins in a landmark decision by India 's Supreme Court in 2001 that decreed all government schools were required to provide free meals to students below the age of 13 . Until that point , the schools had been discharging their commitments to child nutrition `` by giving children 3kg of wheat or rice every month in lieu of giving them meals , '' she said . `` The court said 'This will not do . ' '' Within a year , most states had implemented systems to offer daily meals to their students , but in Bihar -- one of India 's poorest states she said , with a track record of poor governance and social welfare -- it took two years to start providing the service . `` Bihar is always a little bit behind everything , '' she said . `` Around 2004-5 , they started rubbing their eyes and waking up and saying , 'Okay , we 've got to get on this thing . ' '' Read more : Feeding school children in Bangalore . On the whole , the program -- aimed at achieving educational and nutritional goals in one swoop -- has been hailed as a success , with studies showing significant increases in enrollment and attendance , particularly among disadvantaged groups , such as girls , dalits and adivasis , said Khera . `` By and large , it is a very important program and it has had a very good effect . '' But the quality of the service has varied greatly across the country . Some states , such as Rajasthan and Tamil Nadu , developed sophisticated programs to deliver a quality service . By contrast , a 2010 study by India 's Planning Commission reported that more than 70 % of children in schools surveyed in Bihar were unhappy with the quality of their meals , three-quarters of the schools reported they lacked proper utensils , and many schools in Bihar complained of receiving their food supplies on a haphazard basis , resulting in hygiene issues . `` Problems still remain , especially in states like Bihar , Jharkand , Uttar Pradesh , West Bengal , '' she said . `` There is a very serious problem of administrative capacity and law . The implementation is poor , the money they put into the program is very little and so the quality of the food that is provided in this region is a general concern . They 're still struggling with issues that a place like Rajasthan was dealing with 10 years ago . '' The fact that there were no answers days after the tragedy was `` a reflection of the lackadaisical attitude of the Bihar government , '' she said . `` Bihar needs to put mechanisms in place that will allow it to monitor these meals more effectively . '' Further complicating the picture , she said , was the role of private contractors in the food supply chain , motivated by the promise of profiting from the government-funded programs . `` When you bring in contractors to supply meals , these people only come in it for the money . And when they come in for the money , they 're going to skimp any way they can -- by cutting corners , '' she said . CNN-IBN , CNN 's sister network , reported Bihar 's education minister P.K . Sahi as claiming the school principal 's husband was the supplier of the food for the school meals . CNN has been unable to verify his claims with the principal or her husband , who authorities say have `` absconded . '' Khera said that while contaminated school meals were not unheard of across the country , an incident on this scale would hopefully serve as a wake-up call to authorities to improve the service where it was required . `` But it 's hard to see that happening , because there 's a general problem of a lack of accountability , particularly in this state , '' she said .
It provides a free hot meal a day to every child below the age of 13 . It is the largest program of its kind , feeding 120 million children every school day . The scheme is designed to tackle hunger and nutrition in one swoop . But the quality of the food varies wildly , with some states providing substandard food .