This research examines the growth and expansion of public interest environmental litigation (PIEL) in India and analyses the changes that are influencing the development of PIEL in Bangladesh and Pakistan. The necessity for this research lies in the rapid degradation of environment and the need of efficient environmental management in the three countries of the South Asian region. Here, we compare the legal systems of the three countries from the environmental point of view, discuss new ideas and directions and critically analyze the legal provisions that would help to apply environmental norms. These offer the legislators a chance to find out what can be applied in their own region, thus developing their existing legal mechanisms.