The concept of Public Interest Litigation (PIL) originated and developed in the USA in the 1960s.  

• In the USA, it was designed to provide legal representation to previously unrepresented groups and interests.  
• It was undertaken in recognition of the fact that the ordinary marketplace for legal services fails to provide such services to significant segments of the population and to significant interests.  
• Such groups and interests include the poor, environmentalists, consumers, racial and ethnic minorities, and others. 

Source: Laxmikanth