Dear Law Student,
With reference to your inquiry about provisions under which a PIL can be filed, here are 4 points.
1) In High Court, PIL is filed under Art 226.
2) If High Court rejects, PIL, against that order PIL(SLP) is filed in Supreme Court under Art 136
3) When issue is of National Interest, PIL can be filed directly in Supreme Court under Art 32
4) If you live in a town where there is no High Court, then you can file a PIL Civil Suit in Trial Court. These are known as Representative Suits filed under Order 1 Rule 8 of CPC. In foreign countries such suits are known as "Class Action". If you want to challange validity of anly law or section, Suit under Order 27A can also be filed in Court in your town. Suit against Government for negligence etc under Order 27 of CPC.
I hope this will make it clear to you that even if you are living in small town, you have ample power to move local Court for over a 1000 PIL issues.
Haresh Raichura 5/2/17