Bhopal tragedy was caused due to _________________.

Bhopal tragedy was caused due to leakage of poisonous gas from a pesticide factory.
The gas was methyl isocyanate released due to a leak at Union Carbide India Limited company, it was a U.S based pesticide company.
At least 30 tones of methyl isocyanate gas were leaked and killed 6000 people, affected 600000 workers. It is India's major industrial disaster and world's worst industrial disaster.