Step 1: Understanding the Concept:
This question focuses on the historical timeline of major environmental legislation passed by the Parliament of India to safeguard ecosystems and human health.
Step 3: Detailed Explanation:
The Environment (Protection) Act was passed by the Parliament of India in May 1986 and came into force on November 19, 1986.
The enactment was a direct response to the tragic Bhopal Gas Leak disaster of December 1984, which exposed major gaps in the existing environmental regulatory framework.
It was also passed to implement the decisions made at the United Nations Conference on the Human Environment held in Stockholm in June 1972.
This act serves as an "umbrella" legislation, providing a legal framework for coordinating the activities of various central and state authorities established under previous laws like the Water Act (1974) and the Air Act (1981).
Step 4: Final Answer:
The Environment Protection Act was enacted in India in the year 1986.
Therefore, the correct option is (D).