You know there is something really wrong with a country's justice, policing and political system, when out of the people in jail (undertrials, convicts and detenues), minorities and SC/STs comprise a disproportionately high number, as compared to their general population. This shows the bias in administration of criminal justice system and a huge access to justice issue. Click here for the source of the figures. It was quite shocking to read these figures.
The reasons for this is the institutional bias against people from minority communities, especially Muslims in India and against those belonging to the Scheduled castes and scheduled tribes. It is also an issue of access to justice wherein people who need free and competent legal aid most are most forcefully deprived of it.
This seems to be like the issue of African-Americans prisoners in the US jails. The Equal Justice Initiative, under Bryan Stevenson, is doing a great job about the issue of excessive sentencing of under privileged communities in the USA. One must watch this TED video here:http://www.ted.com/talks/bryan_stevenson_we_need_to_talk_about_an_injustice.html