Praise be to Allah.
If a Muslim is living in a country which relies on proper shar’i sighting of the moon to establish the beginning and end of the month, then he is enjoined to follow them with regard to starting and ending the fast. This has been explained in the answer to question number 12660. But if the Muslim is living in a kaafir country or in a country where they tamper with the beginning and end of the month according to their whims and desires, and do not pay any attention to proper shar’i sighting of the moon, then he should follow the closest country to him where they pay attention to sighting of the moon. If he fasts with a country whose moon sighting is reliable, like the land of the Two Holy Sanctuaries, there is nothing wrong with that.
Based on that, if India started to fast one day, for example, after the countries that pay attention to sighting the moon, then it may be said to the one who fasted with them: Do not break the fast with India; rather break the fast with the country which pays attention to moon sighting and make up one day to replace the first day of Ramadan.
And Allaah knows best.