If you are employed in Central/State Govt departments, PSUs, Autonomous bodies and you are applying for a job in other PSU or government job you are needed to submit the NOC from your employer at the time of Interview..
2) Government cannot refuse to give no objection certificate (NOC) to an employee on "vexatious technical grounds" if no public interest was involved, the Central Administrative Tribunal has said.
3) pay protection depends upon several criteria, e.g., the new post being of comparatively higher or lower responsibility, your old scale and new scale, and also the maximum of the new scale not exceeding your basic pay in the old post.