I have a friend from India who got a ticket in Massachusetts for having an invalid license. She had an license from India, and the cop said she needed an international license. However, we found here (see question 5 and appendix C) that an India license should work. My friend is leaving in a month, so I'm wondering if she is able to fight this ticket or if she should just suck it up and pay it.
A traffic ticket lawyer is probably the best bet. They can be in court for you if they have to be. The fees are often not actually too much but it may still be more expensive than just paying the fine.
You may also request a court date, once assigned write a letter to the prosecuting attorney and explain what you found and ask for the ticket to be dismissed. I suspect they would.
I am not a lawyer. That being said, if your friend is a legal driver in India, and has an Indian driver's license, is over 18, and was driving the type of vehicle she is licensed to drive, then India is listed in Appendix C. She should have been a legal driver in Massachusetts. If there was no other infraction noted on the ticket, other than not having a driver's license, and she showed her license to the officer, it would appear she should not have been ticketed. Police Officers are not infallible. Most cannot have every single fact and figure, of every single law, including all appendixes and the sort memorized at all times.
If your friend was living here in the US, when her court date came, she could attend traffic court and be heard by the judge, or magistrate. She would stand accused of not being a legal driver, at which time she could show the documents in question (her license and a copy of what you linked.) Chances are very good the ticket would be thrown out and she would be good to go.
However, you say your friend is leaving to return to India. If she is leaving before her court date, then her only options are to pay the fine or ignore it. Only she can determine what is best for her. If she knows she will never be returning to the US, then ignoring the ticket is less problematic for her. It is unlikely that a simple traffic infraction would ever find its way into the DHS's databases. If there is any chance of her wanting to return in the future, especially to Massachusetts, then regardless of her actual legal status as a licensed driver, she might seriously consider paying the fine and moving on with her life.
If she cannot afford to pay the fine, well, that leaves her in a pickle.
Personal opinion time: were I to be driving in India, legally or not, and be stopped and ticketed by a law officer where I did not have to pay an immediate fine, I would probably leave the country and never worry about it (the ticket) again. There are simply too many people in the world for local police from India to come after me. But that is me.