The marriage was solemnnised in India. However registration hasn't taken place. But that doesn't matter. The marriage is a valid marriage. Registration is simply notifying the government that the marriage be entered in government records which may be used while issuance of visa/passport.

Both are legally married as it was solemnised as per customary Vedic rites and rituals 

If the marriage is solemnize it will be considered as a legal marriage. But it will be compulsory to get the same registered to be legally validated. 

Marriage is valid and legal. The difference between wife and husband is not important as long as both are adults. Registration  can be done anytime after marriage.

You are right sir. 

As far as the marriage is concerned if it was solemnized as per the religious customs and rites then it is held as legally valid even though it was not registered before the concerned marriage registrar.

If both are adult and eligible for marriage by age then there is no legal infirmity in this marriage.

If she is not a foreign citizen, then there is no necessity to register their marriage under special marriage act. 

- If the said marriage was solemnized as per Hindu custom or by a religious custom , then legally that girl become the legally wedded wife of the boy, as marriage registration is not mandatory but compulsory .

- Further, if they want then they can apply for registered the marriage under the Special marriage Act at the place where the boy is residing . 

- However for registration 30 days stay of that girl required legally. 

1. Has the marriage been solemnised by following the customs and rituals as per Hindu Tradition/Religion?

2. If yes, then it is a marriage and the it can be considered as Marriage of Convenience  for want of valid ground in favour of the said allegation.

Dear Client,

The marriage, since solemnized, is absolutely valid in the eyes of law.

Thank you.