Step 1: Understanding the M.C. Mehta Case.
The M.C. Mehta Vs Union of India (1986) case, also known as the Oleium Gas leak case, was a landmark case in environmental law. The Supreme Court ruled that the responsibility for the gas leak, which affected the environment and public health, lay with the industries, and they were liable for the consequences.
Step 2: Explanation of the options.
- (a) Oleium Gas leak: This is the correct answer, as the case was about the gas leak incident.
- (b) Ganga water cleaning: This is not related to the M.C. Mehta case; that case deals with the environment but not the Ganga water.
- (c) Child labour: This is unrelated to the case in question.
- (d) Bonded labour: This is not relevant to this case, which focuses on environmental issues.
Step 3: Conclusion.
Thus, the correct answer is (a) Oleium Gas leak.