SHAFAQNA – The Grand Ayatollah Sistani answered questions about socializing with non-Muslims.
Question: I intend to travel to India. Are the Hindus, Christians, Zoroastrians, Najis, and what is the ruling about socializing with them?
The Grand Ayatollah Sistani: Christians and Zoroastrians are ruled to be clean, and there is no problem in itself to socialize with them and other disbelievers (who do not follow a book).
Question: What is the ruling about eating with disbelievers?
The Grand Ayatollah Sistani: If the disbeliever is idol worshiper and polytheist, and touches the food with wetness of his hand or body, it is Najis, and there is problem eating the food; otherwise it is not Najis. Therefore, if we doubt touching with wetness, it is clean, and disbelievers who follow book (Jews, Nasrani) are also clean.
Source: PERSIAN SHAFAQNA