Iyer made notable contributions in the field of constitutional law, focusing on social, political, and civil rights. He was noted for his use of literary references in his judgments. This revolutionary tool, initially used by public-spirited citizens to file PILs on behalf of sections of society unable to on their own, continues to bring in unheard changes in the day-to-day lives of the people even now, decades later. Observing this, he states: ?
Jurisprudence during the Emergency In June 1975, the Allahabad High Court had ruled that Prime Minister
Indira Gandhi's election to Parliament was unlawful, and barred her from it for another six years. Iyer was on the bench that heard an appeal against this order in the Supreme Court. In
Indira Gandhi v Raj Narain, he ruled that although Mrs. Gandhi could no longer be a Member of Parliament, she was entitled to retain her position as Prime Minister. Interpreting this as losing the popular mandate to rule, the Opposition called for her resignation. The next day she declared a
state of Emergency in the country.
Social Rights Iyer wrote judgments in several notable cases concerning social rights. These included
Maneka Gandhi v. Union of India, in which he held that Article 21 of the Indian Constitution, which protects the right to life and liberty, must be interpreted widely to include several social rights. In the Ratlam Municipality case, he started a trend for judges to leave the courtroom and go out and see, the situation on the ground. Moreover, this case would be a forerunner of cases which would be decided later on, on the concepts of "
precautionary principle", "
polluter pays" and "
sustainable development". In Muthamma's case, Iyer called for breaking the 'glass ceiling' with gender parity in traditional practices in public employment.
Civil and Political Rights Iyer ruled in several cases that aimed to secure against custodial violence, ruling on bail conditions as well as regarding legal aid for detainees. In
Ediga Anamma v State of Andhra Pradesh, he established the jurisprudence governing the commuting of death sentences to imprisonment for life, identifying mitigating factors that could be applied in such cases. ==Public life post-retirement and death==