Union of India, a division bench of the Supreme Court has read down exception 2 to section 375, Indian Penal Code (IPC), holding that sexual intercourse by a man with his minor wife would be rape.
"We are left with absolutely no other option but to harmonise the system of laws relating to children", justice Madan Lokur said in his decision.
The court said sexual intercourse with a girl below 18 is rape regardless of whether she is married or not.
The United Nations calls child marriages "an appalling violation of human rights and robs girls of their education, health and long-term prospects".
".in my view, because of the patriarchal nature of our society, some extra benefit must be showered upon the girl child to ensure that she is not deprived of her right to life".
The SC said exception in rape law was discriminatory, capricious and arbitrary and that social justice laws were not being implemented with the spirit they have been enacted.
The apex court said the exception is violative of Article 14, 15 and 21 of the Constitution.
"Unfortunately, this report deals with girls below the age of 19 years and not 18 years, but the report does indicate that more than 20 percent girls in this country are married before attaining the age of 18 years". Therefore, it does appear that only a notional or linguistic distinction is sought to be made between rape and penetrative sexual assault and rape of a married girl child and aggravated penetrative sexual assault.More news: Trump lashes out at Puerto Rico as House weighs aid package
The bench noted that the artificial distinction was contrary to the philosophy and ethos of Article 15 (3) of the Constitution as well as contrary to Article 21 of the Constitution and our commitments in worldwide conventions.
On Thursday, sociologist Ranjana Kumari welcomed the court verdict and said it had removed a conflicting position in Indian laws. It is also estimated that there are about 23 million child brides in the country. All these costs eventually add up and apparently only to support a pernicious practice, it said.
Indian law says a woman must be at least 18 to marry and consent to sex, but there are exceptions. While the national age of consent is 18, young girls forced into child marriage before that age have had little protection against statutory rape.
As per the Apex Court, any sexual relations with an underage girl by a man will be considered illegal and seen as rape, eliminating a crucial loophole.
By ruling that marriage can not be a licence to have sex with a minor girl, the Supreme Court has corrected an anomaly in the country's criminal law.
The petitioner had also argued that the fact that age of consent is 18 years is indicative of the fact that Parliament considers girls below the age of 18 years as incapable of giving consent for sex.
The Court also urged the Central and State governments to take proactive steps to prevent child marriages, while making it clear that it has not gone into the larger issue of marital rape.