The roots of Public Interest Litigation can be traced from the concept of action popularis of Roman Jurisprudence. In common parlance, the aggrieved party has the locus standi to approach the Court for seeking redressal to the grievances. However, through PIL it is axiomatic that locus standi is liberally interpreted enabling a pro bono publico to file a petition. The courts can also take suo moto cognizance. In making a reference to the Realist School of jurisprudence PIL can be stated as the judge led and judge induced strategy germinating from the oath which a judge takes for negating injustice. The judges even accepted letters and telegrams as petitions. As per the Sociological Jurisprudence it is an approach where the Judges are concerned with the actual functioning of the Law in its true sense and spirit by reaching out to the masses for the progressive society rather than its abstract content. Justice P.N. Bhagwati and Justice Krishna Iyer can be said as pioneers of PIL. PIL is a product of Judicial Activism in India; it can be filed in the Supreme Court under Article 32 and in the High Court under Article 226 of the Constitution of India.
In the very first PIL in 1976, Mumbai Kamgar Sabha v. M/s. Abdulbhai Faizullabhai and others (1976 (3) SCC 832) J. Krishna Iyer gave proactive judgment; in the case of D.K. Basu v. State of West Bengal[(1997) 1 SCC 416] the Court took action based upon the letter seeking urgent attention to the custodial deaths in West Bengal. The judgement in the case of Vishakha v. State of Rajasthan(AIR 1997 SC 3011) promotes enforcement of gender equality and created a revolution by laying down the guidelines to be followed for curbing the menace of sexual harassment of women at workplace. In Hussainara Khatoon v. State of Bihar(1979 SCR (3) 532) the Court was made vigilant on the conditions of the under trials who were in untenable detention pending for trial. The Judiciary has also acknowledged the right of the Mother Nature to place a plea for the protection by redressing to the series of M.C. Mehta Cases which forms the important ingredient of Environmental Jurisprudence in India
In the largest and populous democracy of the globe, where a strong percentage of the population comprises of the unrepresented group-vulnerable and downtrodden PIL serves as strong voice to the voiceless voices, thereby bridging the gap between the aggrieved and the justice. However the boon of PIL is to be used piously for the welfare of the society at large and not to satisfy any ulterior gains furthermore, on no account it should be frivolous in nature.
