The term 'illegal stoppage of work' is not defined in the ID Act, but only strike is defined, and a strike becomes illegal when it is commenced in contravention of sections 22 and 23 of the Act. As per section 2(q), strike means the cessation of work. Cessation of work shall be interpreted as the stoppage of work. Therefore, stoppage of work without notice (section 22) and while conciliation is in process or pending (section 23) shall be considered as an illegal strike (section 24). The rest, you know.
Regards,
Madhu.T.K