The right to change jobs (whether for better or worse) is a fundamental right, though airlines in India do not think so.
Under the guise of affecting a public service DGCA stepped in under pressure from airlines, by introducing a 6 month notice period for pilots to serve airlines they are employed with before quitting. This has been in effect over the past couple of years!
Besides, it is mandatory for pilots to get an NOC from DGCA to join another airline. Therefore, this choice favours an employer more than an employee.
If this is not arbitrary slavery then what is??