The Supreme Court evolved the following principles:
- The Court, under Articles 32 and 226, can entertain petitions from interested persons in welfare of disadvantaged people, and is constitutionally bound to protect their Fundamental Rights.
- For issues of public importance and fundamental rights enforcement, the court treats letters/telegrams as PIL, relaxing procedural laws.
- The court will invoke Articles 14 and 21 and International Conventions on Human Rights when injustice is meted out to large numbers of people.
- The common rule of locus standi is relaxed to enable the court to address grievances of the poor, deprived, illiterate, and disabled.
- If prima facie satisfied about violation of constitutional rights of disadvantaged groups, the Court may not allow State/Government to question maintainability.
- Procedural laws apply, but principles like res judicata depend on petition nature.
- Disputes between warring groups purely in private law will not be agitated as PIL.
- In appropriate cases, even if petitioner has private interest, the Court may inquire into state of affairs in public interest.
- The Court in special situations may appoint Commission or other bodies to investigate allegations and facts, or direct management of public institutions.
- The Court will not ordinarily transgress into policy and will take utmost care not to transgress jurisdiction while protecting rights.
- The High Court, though able to pass orders for complete justice, does not have a power akin to Article 142 of the Constitution of India.
- Ordinarily, the High Court should not entertain a writ petition by way of PIL questioning constitutionality or validity of a statute or a statutory rule.