Most child marriages  in the world take place in South Asia and rural sub-Saharan Africa. In rural India, 47 percent (UNFPA report ) of girls get married before the age of 18. The Indian state of Bihar has the highest number of child marriages  at 69 percent.
Urmila Chanam  shares a story of a child bride in India:
This is the tradition in this part of India. Children are married off when they should still be playing with toys. Boys and girls enter matrimony without knowing what marriage means. Their childhood and any life aspirations they might have had are extinguished by this age-old tradition. No one challenges it because it has become the norm. [..]
Though Indian law has made child marriage illegal, it is still reported widely from the rural parts of Madhya Pradesh, Uttar Pradesh, Rajasthan, Chhattisgar, Bihar, and Andhra Pradesh. Though some other third world countries practice child marriage, India alone houses one-third of all child brides.
There are also religious reasons for early marriages. The high court of the Indian state of Karnataka  has recently ruled in a child marriage case that  the Prohibition of Child Marriage Act 2006 (PCMA) has overriding effect over the provisions of the Muslim Personal Law, where the marriage of a girl child is allowed once she attains puberty.
According to the PCMA act marriage below 18 for girls and 21 for boys is prohibited. Rural girls and boys who are poor, have little or no education and bonded by traditional social norms and values are most likely to get married early defying the legislations. But that is always not the case. Maharashtra has one of the highest numbers of child marriages. Video Volunteers at Youth Ki Awaaz  reminds:
Fifty-two per cent of married women in Maharashtra admit to consummating their marriages before the age of 18, a government’s District Level Household and Facility Survey (DLHS-3) report reveals. This is happening in a so- called ‘progressive’ state of Maharashtra, the family controls a girls life and reproductive decisions.
But the situation is changing. IndiaUnheard (Video Volunteers)  Community Correspondent Rohini Pawar  interviews two girls who recently saw their friend getting married. Both are thankful that it wasn't them:
Twelve women, who had all been married as children, participated in this video  speaking out against child marriage. This video and project was the beginning of Video Volunteers’ Community Video Unit Program:
The above video was screened in many villages on wide screen projectors.
Child marriages in India are a part of the larger social construct which is not commonly flagged as a problem. Neha , a blogger from New Delhi, writes:
Although the UN has been working hand in hand with the government of India to raise awareness, strengthen law enforcement and invest in the education of girls, many of our leaders still consider child marriage as a solution to protect girls from sexual atrocities like rape.
According to UNFPA  if current levels of child marriages worldwide continue, every single day 39,000 girls will marry too young.