seem to be clarified in these articles How Anderson Was Allowed To Get Away and Is it too late to ask Arjun Singh about Bhopal?. From the second article:
"The fulmination against Anderson is fashionable but futile. So too is the excoriation of Judge Mohan P Tiwari, the chief judicial magistrate of Bhopal. He is under attack because he handed out only two-year sentences to the accused in the Bhopal Gas Tragedy trial.
How exactly is it Judge Tiwari's fault?
On September 13, 1996 the Supreme Court ruled that the accused would be tried under Section 304 A of the Indian Penal Code rather than Section 304 Part II. Section 304 Part II deals with culpable homicide; Section 304 A refers to death caused by negligence. It is not a subtle difference.
What is more, if found guilty under Section 304 A the maximum sentence is two years. The chief judicial magistrate of Bhopal handed down the heaviest punishment within his power. He could not overturn a Supreme Court ruling and try the accused under a different section.
Justice A M Ahmadi, who was chief justice of India in 1996, has asked why a review petition was not filed against his ruling. Rachna Dhingra, an activist, says precisely such a review was filed by the Bhopal Gas Peedit Sahyog Samiti fourteen years ago; it was, she says, rejected without giving any reasons.
The prime minister says he is setting up a new group of ministers to re-examine the issue. It is a waste of time and energy. The chance to question Warren Anderson in any meaningful manner came and went on December 7, 1984. Handing out lengthy sentences was not on the books once the Supreme Court decided to try the accused under a section where the maximum sentence cannot exceed two years.
Warren Anderson is not coming back to India. Those who stood trial are, most probably, not going to get a more severe sentence. But is it too late to question Arjun Singh, and is it too late to draw appropriate lessons where the Nuclear Liability Bill is concerned."