http://www.cogia.de/en
This is good tool for sentiment analysis using facebook, tweeter, forum and blog comments

I feel this can be a very good community based opensource exercise. Directly I am not sure about any tool that will fit the need. Most of the tools are for filtering emails for spams like apache SpamAssassin. In any case the rules needs to be developed which will be very local and specific to Indian needs, and will require most of the effort rather than the tool development itself.

Name of the software: Umbrella,
Details of the software: Category-Based Filtering, Whitelists and Blacklists, Block Page Bypass, Whitelist-Only,
Vendor: OpenDNS,
Relative Merits: Reliable filters, also an alternative to ISP's DNS service, this worthwhile free service helps make web surfing safer, convenient and more trustworthy.

using an Machine Learning tool we possible to use the filter before publish in to the market.the Ml tool is use to the its taken example an image the machine can learn the image first and based on if we don't want to publish its tool is filter by internaly..

With the help of some existing toll like alfresco , Drool, and Hadoop along with some custom programming we can achieve the required solution.

Using content filtering services like fortinet, etc can prove to be useful for the situation at hand.

For web content filtering ,real-time content analysis analysis and categorization engine the 'bloxx' software is a very good for that.
for more information about the software and vendor login to http://www.bloxx.com/.

The one method available is reporting by viewers of such content. We need to have eligible (knowledge of Indian constitution, LLB) public officials for the purpose, who can remove such sensitive material after reported upon by even a single individual. Ist - Such posts should only be suspended and not permanently removed by the concerned official. 2nd -Such official should however intimate this to the senior officers, who should decide whether to remove it, initiate some penal action etc.

"R" tool. This tool will fulfil this requirement & much more.

Here we have some useful information.