There has been a decline in the rate of child marriages among young girls in India but the progress is not sufficient to guarantee their right to education and self-determination, the UN has said.

The UN today marked the first 'International Day of the Girl Child', focusing on the theme of calling for an end to child marriage and stressing that education is one of the best strategies for protecting girls against this "harmful practice."

The United Nations Population Fund (UNFPA) has announced that it will invest an additional USD 20 million over the next five years to reach the most marginalised adolescent girls in 12 countries with high rates of child marriage. The countries to be focused on include Guatemala, India, Niger and Zambia.

According to UNFPA's report 'Marrying Too Young: End Child Marriage', which was released today, in India 47 per cent of women between 20 to 24 years of age had married or entered into union by 18 during 2000-2011.

Of these 47 per cent women, 56 per cent lived in the rural areas and almost 30 per cent in urban households. Nearly 76 per cent of the girls had no education. Further, 75 per cent of the young girls hailed from the poorest of the poor households and 16 per cent from the rich households.

Data from three consecutive household surveys in India showed that the rate of child marriage among girls under age 15 is declining at more than twice the rate than among girls under 18 years of age.

The decline for girls under 15 years of age is 30 per cent as compared to 13 per cent reduction for girls under the age of 18.

"While this can be interpreted as a sign of progress, it is still not sufficient to guarantee children their full rights in terms of education, sexual and reproductive health and the right to self-determination," the report said.

The report said wide variations in the prevalence of child marriage were found within India. Citing data from a 2006 National Family Health Survey (NFHS), it said that Indian states such as Goa, Manipur and Kerala have prevalence rates of 15 per cent or less (11 per cent, 13 per cent and 15 per cent, respectively).

At the opposite extreme, in a number of states, at least half of girls are married or in union before age 18, such as in states like Uttar Pradesh (53 per cent), Andhra Pradesh (55 per cent) and Bihar (60 per cent).

Globally, despite efforts to decrease the practice of child marriage, the frequency of child marriage has remained level over the last decade, the report said.

The report pointed out that if current trends continue, the number of girl child marriages will increase dramatically over the next 10 years.

By 2030, the number of child brides marrying each year would have grown from 14.2 million in 2010 to 15.1 million, up nearly 14 per cent if current trends continue, the report said.

One in three girls in developing countries (excluding China) will be married before 18 and one out of nine girls will be married before their 15th birthday, the report said..

"Most of these girls are poor, less-educated, and living in rural areas," the report added.

In his message to mark the day, UN Secretary-General Ban Ki-moon stressed that education for girls is one of the best strategies for protecting them against child marriage.

"When girls are able to stay in school and avoid being married early, girls can build a foundation for a better life for themselves and their families. Let us do our part to let girls be girls, not brides," Ban stated, urging governments, community and religious leaders, civil society, the private sector, and families, especially men and boys, to promote the rights of girls.

The UNFPA report said girls' vulnerability to child marriage can increase during humanitarian crises when family and social structures are disrupted.

In times of conflict and natural disaster, parents may marry off their young daughters as a last resort, either to bring the family some income in time of economic hardship, or to offer the girl some sort of protection, particularly in contexts where sexual violence is common.

Girls who were married off early in food-insecure Kenya were called 'famine brides'. Young girls were married to "tsunami widowers" in Sri Lanka, Indonesia and India as a way to obtain state subsidies for marrying and starting a family, the report said.

During the conflicts in Liberia, Uganda and Sudan, girls were abducted and given as "bush wives" to warlords, or even given by their families in exchange for protection.

The International Day of the Girl Child was designated as October 11 by a resolution adopted by the UN General Assembly in December last year to recognise girls' rights and highlight the unique challenges girls face worldwide. The theme of this year's observance was 'Ending Child Marriage'.

Approximately 70 million young women today were married before 18, according to the UN, which noted that child marriage denies a girl her childhood, disrupts her education, limits her opportunities, increases her risk of being a victim of violence and abuse, and jeopardises her health.