Public interest litigation

Hi! Thanks for the question! 

When you file a PIL in High Court/Supreme Court will call you alone if you don't engage a lawyer( For the arguments with the other party). If you engage a lawyer, then he will accompany you. The court doesn't proceed in person. All the necessary parties and people will be present. 

The court will hear the arguments from both the side in the open court as the law provides.

As your question was not clear enough, I answered with what I could gather. Please put forward any further questions if there. 

Any Indian citizen can file a PIL, the only condition being that it should not be filed with a private interest, but in larger public interest. At times, even the Court can take cognizance of a matter if it is one of utmost public importance, and appoint an advocate to handle the case.

Yes a letter can be considered as a PIL.