Discuss why we cannot have a corruption reducer index to check the position of corruption in a every department of a State.A corruption index is a...

There are a couple of approaches in answering this
question.  The first would be that, to a great extent, the presence of the 24 hour news
cycle helps to establish a "corruption index."  The inescapable presence of the media is
something that provides immediate access and examination of corruption.  For example, in
the Indian state of Karnataka, a judicial report about illegal land dealings was made
public and in about a week, the pressure was brought to bear for the Chief Minister of
the state to resign.  This pressure, a form of "corruption index," was brought to bear
by the news media.  The constant presence of news, enhanced by online forums and 24 hour
news networks, makes it very difficult for public officials to operate as "business as
usual" in terms of corruption.  In this light, the news media has the ability to operate
as a form of "corruption index."

In another sense, part of
the reason why there cannot be an exact "corruption index" has to do with logistics. 
What is the exact measure of corruption is difficult to define, so elusive of a
definition that it cannot be fed into a mechanism and gauged with a numeric reading. 
For example, pollution can be directly measured.  There is "X" percent of contaminants
in a given sample.  In the issue of political corruption, the issue is much murkier
because of the close line between business dealings and corruption.  Identifying and
stating degrees of collusion between business and politics is difficult because of the
human element.  For example, again going back to India, how does one quantify the 2G
Telecom scam in a numeric reading?  The corruption index is a difficult idea to
institute because of its nebulous state.

Another reason why
a corruption index would be difficult to institute comes down to an issue of control. 
Essentially, the problem resides in who is in control of the corruption index.  In
nations where corruption is so rampant, there is such a strong collusion between the
public and the private realms that it is near impossible to find a non- corrupted
element in either.  A third party that is outside government and private business would
have to be in charge of the "corruption index." If the government is corrupt, then it
could not really be trusted to police itself with the index, as this would become a tool
of corruption.  If the government is corrupt with private business, then this makes both
realms unable to be seen as an arbitrator to prevent corruption. (See 2G scam
revelations that the Prime Minister and members of his cabinet knew about the collusion
between business and government.)   This makes the media a prime candidate.  In late
June, Indian Prime Minister Singh argued that the media is "judge, jury, and
executioner."  This helps to bring to light that the media has a role in the monitoring
of corruption and can be seen as a "corruption index" of sorts.