Dear friend,
To me, the framing of your
very question seems partly vague and partly superfluous.
First, under which law you seek the notification relating to exemption from licensing when the no of workmen falls below 50 is not known.
Second, there are explicit provisions in the ESI Act,1948 and EC Act,1923 about the applicability to certain class of employees covered or not covered by them.
Therefore, no separate notifications are necessary as the provisions of the above Acts are self-explanatory.
On the contrary, in fact notification is necessary, only if the State Governments were statutorily authorised to amend the threshold no. i.e., reducing the minimum no. of employees for the purpose of coverage only as in the case of CLRA Act,1970 like which are Central Acts which can be enforced by both the Governments within their respective spheres of jurisdiction.