China has 9.02 million left-behind children, according to a statement from the Ministry of Civil Affairs (MCA) on Thursday following a census carried out this year.

The census was jointly conducted by the MCA, the Ministry of Education and the Ministry of Public Security and began in March. Left-behind children is the term used to refer to rural children under 16 whose parents are migrant workers or who have one migrant-worker parent and the other incapable of guardianship.

Over 90 percent of the left-behind children live in China's central and western regions, which are less developed than China's eastern regions, thus, have more people leaving to seek work elsewhere.

Among all the left-behind children, 8.05 million, or 89.3 percent, are in the care of their grandparents and 3.3 percent are looked after by other relatives, while four percent have no guardian at all.

"The flow of migrant workers driven by urbanization has affected the family unit and many parents lack a real awareness of their responsibilities," said Tong Lihua, director of a Beijing-based legal aid organization for teenagers.

In June, 2015, four siblings in southwest China's Guizhou Province died after drinking pesticide, three were under 10-years-old. Their mother had left the family and their father had migrated for work. The children had lived without a guardian for about two years.

The statement included an announcement about a guardianship program, proposing that when left-behind children are found to be living alone their parents must return to care for them or find alternate, reliable guardians for them.

The program aims to ensure that all left-behind children are under proper care by the end of 2017.