The IT/ITeS employees unions have done a good job and have affillaited with trade unions and can agitate against it and pull the publisher and NSR to court of law.
The employees need to unite.
Other than law enforcement agencies no none can indulge into such checks and not at all into such practise say: blacklisting.
The unions can also display the list of blacklisted Managers/Employers in its offices and amonsgt its members.
You may go thru:
https://itnitesunion.wordpress.com/2010/06/23/in-nsr-can-a-employee-be-black-listed-i-am-asking-this-as-some-employers-have-said-this-to-employees/
https://www.lawyersclubindia.com/forum/Blacklist-by-nasscom-66328.asp#.VdBj7bV-jMo
https://www.lawyersclubindia.com/forum/Bpo-s-call-centers-mnc-s-65172.asp#.UbyA3OeAqWM
https://communities.nasscom.in/discussion/topics/473669/messages
https://www.pathlegal.in/can-a-company-blacklist-an-employee-for-abdconding-in-nasscom--Q000000000293767.php
https://www.change.org/p/som-mittal-stop-blacklisting-of-employees
https://in.answers.yahoo.com/question/index?qid=20080409043135AAMOSMS
https://www.quora.com/What-is-NASSCOM-Can-any-IT-company-blacklist-any-employee-via-NASSCOM
https://www.quora.com/Can-an-employer-blacklist-an-employee-on-NASSCOM
https://www.citehr.com/48102-employee-blacklisting.html