Kevin Frayer via Getty Images 'Left behind' children from right to left, Luo Gan,10, Luo Hongniu, 8, Luo Lie, 5, and Luo Hongni, 11, walk together while doing chores in the fields on December 18, 2016 in Anshun, China.

When parents living in rural China seek work in urban areas, they are usually forced to leave their children at home to be raised by family members like grandparents. These children, of which there are an estimated 60 million, are China’s “Left Behind” children.

China-based Getty Images photojournalist Kevin Frayer followed the four Luo siblings, who live with their elderly grandparents in Anshun, China. Frayer photographed the children while attending school, in the playground and on the family farm.

Frayer explained that it is China’s hukou documentation system, which dictates that education and health care are accessible only in the district where a child is born and registered, that forces many children to stay behind in rural areas. Local schools, educators and community charities often struggle to fill the gaps the parents’ absence causes.

Kevin Frayer via Getty Images Luo Lie, 5, uses chalk to draw a picture on a wooden door of the family home. In the case of the Luo grandparents, who are elderly and poor, they do what they can to meet the basic needs of four children between the ages of 5 and 11.

Kevin Frayer via Getty Images Luo Hongniu, 8, holds flowers she picked while doing chores.

Kevin Frayer via Getty Images Luo Hongniu, 8, hangs laundry after washing clothes with her siblings.

Kevin Frayer via Getty Images Luo Hongni, 11, collapses from the weight as she carries flowers while doing chores in the fields.

Kevin Frayer via Getty Images Grandfather Luo Yingtao, 64, carries his grandson Luo Lie, 5, to bed at the family house.

Kevin Frayer via Getty Images Luo Hongni, 11, throws a stone as she tends to one of the family's cows.

Kevin Frayer via Getty Images Luo Hangni, 11, right, does exercises with classmates at a local school. Local schools, educators and community charities often try to the fill the gaps of being without a mother and father.

Kevin Frayer via Getty Images Luo Lie, 5, right, does eye exercises with classmates. Many children feel the absence of interaction with their mother and/or father, creating a generation of lonely kids who experts worry may be prone to anxiety, poor school performance, and depression.

Kevin Frayer via Getty Images Like millions of Chinese children, the four Luo siblings are being raised by their grandparents in rural China as their parents left to find work in urban areas. Joining parents in the city is not usually an option, as China's hukou documentation system dictates that education and health care are accessible only in the district where a child is born and registered.

Kevin Frayer via Getty Images Luo Gan, 10, stays warm by a fire at the family house.

Kevin Frayer via Getty Images Luo Hongniu, 8, leans on hay bales while doing chores.

Kevin Frayer via Getty Images Luo Hongni, 11, waits outside her class at a local school.

Kevin Frayer via Getty Images Luo Hongni, 11, top and sister Luo Hongniu, 8, play in hay bales.

Kevin Frayer via Getty Images Luo Lie, 5, walks home from school. China's government says it is making child welfare a national priority, and will work to improve support to 'left behind' children after launching its first-ever national census to assess the problem.