Does a Foreigner also has an authority to file a PIL?

Yes. Even Foreigners who reside in India or visiting India on visas also have certain constitutional and statutory rights. If any of their rights are tampered or infringed or threatened in India, they have full authority and equal rights as citizens of India, to move the court for its intervention by way of a Public Interest Litigation (PIL)., if the issues are such of a kind that the concerned people or a section of them are not in a position to themselves reach out to court for relief.

Some public spirited person or a group or an association of such persons (foreigner’s) can file a PIL seeking relief for them. However, the authority of entertaining the PIL is completely the court’s discretion.