When did the Bhopal gas tragedy occurred?
On the night of December 2 1984, one chemical known as methyl isocyanate spilt out from the Union Carbide India Ltd’s means UCIL's pesticide factory. That turned the city of Bhopal into a huge gas chamber. It was the first major industrial accident and popular as Bhopal gas tragedy.
From the above facts show the correct answer the Bhopal gas tragedy occurred in 1984. Thus correct option is D. Other option are irrelevant.