In MNCs and BPS companies, HR does have the ability to blacklist a candidate on NASSCOM if necessary. This action is typically taken in cases where a candidate's conduct or performance raises concerns that warrant such a decision. When it comes to background verification, HR may indeed refer to NASSCOM data if the candidate has been registered with them. The NASSCOM Skill Registry data plays a significant role in background verification processes as it provides insights into a candidate's skills, qualifications, and professional background. Employers often use this information to validate the authenticity of a candidate's claims and ensure they meet the required standards for the position.