Explanation:

Bhopal gas tragedy of 1984 took place because methyl isocyanate reacted with ammonia.
The Bhopal disaster, also referred to as the Bhopal gas tragedy, was a gas leak incident in India, considered the world's worst industrial disaster.
It occurred on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh. Over 500,000 people were exposed to methyl isocyanate (MIC) gas and other chemicals. The highly toxic substance made its way into and around the shanty towns located near the plant.