The primary objective of PIL in India is to protect the rights of individuals and groups, including those related to the environment.

In the landmark case of M.C. Mehta v. Union of India (1985), the Supreme Court of India recognized the locus standi of environmental groups in PIL cases, allowing them to represent the interests of the environment and seek legal remedies.

The 'Polluter Pays' principle is a fundamental principle of environmental law that holds polluters financially responsible for the environmental damage they cause. It aims to deter pollution and encourage industries to adopt cleaner production methods.

In the PIL case of Rural Litigation and Entitlement Kendra v. State of Uttar Pradesh (1985), the Supreme Court ordered the closure of hazardous industries in the ecologically sensitive Doon Valley in Uttarakhand, recognizing the need to protect the environment from industrial pollution.

The 'Precautionary Principle' is a principle of environmental law that requires decision-makers to take preventive measures to avoid potential environmental harm, even if there is no conclusive scientific evidence of the harm.

In the PIL case of Himachal Pradesh Pollution Control Board v. State of Himachal Pradesh (2010), the Supreme Court banned the use of plastic bags in the state of Himachal Pradesh, recognizing the harmful impact of plastic pollution on the environment.

Environmental impact assessment (EIA) plays a crucial role in PIL cases related to environmental protection by assessing the potential environmental impacts of proposed projects, promoting public participation in environmental decision-making, and strengthening the role of government agencies in environmental regulation.

In the landmark PIL case of M.C. Mehta v. Union of India (1985), the Supreme Court ordered the government to take steps to clean up the Ganga River, recognizing the river's cultural and religious significance and the need to protect it from pollution.

The 'Public Trust Doctrine' is a legal principle that recognizes the public's right to access and use natural resources, imposes a duty on the government to protect natural resources for future generations, and promotes sustainable development and conservation of natural resources.

In the PIL case of Arjun Gopal v. Union of India (2018), the Supreme Court banned the use of firecrackers during Diwali in Delhi, recognizing the harmful impact of air pollution on public health.

The 'Sustainable Development' principle is a legal principle that promotes economic development while protecting the environment, encourages the use of renewable energy sources, and promotes public participation in environmental decision-making.

In the PIL case of T.N. Godavarman Thirumulpad v. Union of India (2013), the Supreme Court ordered the government to take steps to protect the Western Ghats, a biodiversity hotspot in India, recognizing the need to conserve ecologically sensitive areas.

The National Green Tribunal (NGT) is a specialized court that handles environmental cases, promotes public participation in environmental decision-making, and strengthens the role of government agencies in environmental regulation.

In the PIL case of M.C. Mehta v. Union of India (1985), the Supreme Court banned the use of certain pesticides in agriculture, recognizing the harmful impact of pesticides on human health and the environment.

The 'Right to a Healthy Environment' is a legal principle that recognizes the right of individuals to a clean and healthy environment, imposes a duty on the government to protect the environment, and promotes sustainable development and conservation of natural resources.