Background.
The International Day for the Abolition of Slavery, 2 December, marks the date of the adoption, by the General Assembly, of the United Nations Convention for the Suppression of the Traffic in Persons and of the Exploitation of the Prostitution of Others
( resolution 317(IV)  of 2 December 1949). The focus of this day is on eradicating contemporary forms of slavery, such as trafficking in persons, sexual exploitation, the worst forms of child labour, forced marriage, and the forced recruitment of children for use in armed conflict.
Main Forms of Modern Slavery.
Slavery has evolved and manifested itself in different ways throughout history. Today
some traditional forms of slavery still persist in their earlier forms, while others have
been transformed into new ones.
The UN human rights bodies have documented the persistence of old forms of slavery
that are embedded in traditional beliefs and customs. These forms of slavery are the result of long-standing discrimination against the most vulnerable groups in societies, such as those regarded as being of low caste, tribal minorities and indigenous peoples.
Forced labour.
Alongside traditional forms of forced labour, such as bonded labour and debt bondage
there now exist more contemporary forms of forced labour, such as migrant workers, who have been trafficked for economic exploitation of every kind in the world economy: work in domestic servitude, the construction industry, the food and garment industry, the
agricultural sector and in forced prostitution.
Child labour.
Globally, one in ten children works. The majority of the child labour that occurs today is
for economic exploitation. That goes against the Convention on the Rights of the Child ,
which recognizes “the right of the child to be protected from economic exploitation and
from performing any work that is likely to be hazardous or to interfere with the child’s
education, or to be harmful to the child’s health or physical, mental, spiritual, moral or
social development.”
Trafficking. 
According to the Protocol to Prevent, Suppress and Punish Trafficking in Persons
Especially Women and Children , trafficking in persons means the recruitment,
transportation, transfer, harbouring or receipt of persons, by means of the threat or use of force or other forms of coercion for the purpose of exploitation. Exploitation includes
prostitution of others or other forms of sexual exploitation, forced labour or services,
slavery or practices similar to slavery, servitude or the removal of organs. The consent of the person trafficked for exploitation is irrelevant and If the trafficked person is a child, it is a crime even without the use of force.