According to 1860 Indian Penal Code:
"Sexual intercourse by a man with his own wife is not rape."
What are the possible exceptions to this law that would allow for a husband to be prosecuted for raping his wife?
The simple answer is: if the law says marital rape is not a crime, it is not punishable by the criminal justice system. If there were a loophole, one of the lawyers representing one of the many rape victims who have been seeking justice in India would have found it. There more than likely isn't one.
Some Indian marital rape victims have tried prosecutions under the domestic violence laws, but as I understand it -- and I'm no expert -- those laws are fairly toothless.
The solution is for India to pass better laws. The majority of Indian judges and legislators want marital rape to be allowed, and as long as that's the case, unfortunately, no clever workaround is going to fix anything.
The Protection of Women from Domestic Violence Act, 2005 does prohibit forced sexual intercourse in a marriage. However, this Act provides civil remedies only. Marital rape has not yet been criminalised, although it is violative of the right to life under article 21 of the constitution.
There have been various petitions for the formation of a law to criminalise marital rape and hopefully we will see such a law being passed in the near future.