Dear Akhil,
Your confusion is quite natural because of the re-occurrence of the same term "Industrial Establishment" in various chapters of the Industrial Disputes Act,1947 with different meanings. But you can certainly dispel this confusion with a little more effort of re-reading with reference to the context wherever it is used.
In common parlance, every establishment carrying on any activity pertaining to an industry is an industrial establishment. Such activities may be that of manufacturing, mining,exploration of oil and allied products,business/trading including buying and selling of goods and commodities, rendering services like transportation of people and goods, telecommunications,hospitality, education, health-care, entertainment etc., commercial activities like banking, non-banking financial activities, insurance and so on.
But the complex nature of social life is such that every activity irrespective of its nature and purpose requires hiring of the services of human beings for some reward that can be either material or otherwise.Take for example the running of a temple or a church. It is basically and essentially a religious activity aiming at spiritual benefits to its followers. But such a religious institution/undertaking may engage itself in certain other activities too like running lodging houses, transportation, renting out buildings, selling of religious artefacts and prasads in large scale etc., analogous to trade or business.It can be separable from the main spiritual activity of the temple or church. Therefore, that particulr severable activity is an industrial establishment. Similarly, the predominant activity of the undertaking being analogous to industry and the other non-industrial activities of the undertaking are not separable, then the entire undertaking is an industrial establishment for the purpose of the ID Act,1947.That is the exact purpose and meaning of the term " industrial establishment " as defined u/s 2(ka) of the ID Act in its chapter I.
Chapter V-A of the Act deals with Lay-off and retrenchment of certain workmen and closure of the establishment generally and specifically with reference to industrial establishments employing less than 100 workmen on an average in a period of 12 months prior to lay-off/ retrenchment/ closure as the case be.
Here, the Act has to differentiate the establishments in terms of the application of this chapter as well as the pre-fixed no of workmen. Therefore there is another definition of the term "industrial establishment" with an explanation of clarifying nature u/s 25-A for the specific purposes of this chapter only. They are (1) those establishments to which chapter-VB does not apply or Such of the Factory or Mine or Plantation where less than 50 workmen are/were employed or a seasonal establishment. For these establishments no necessity for obtaining permission for lay-off or retrenchment or closure is necessary. Regarding compensation for lay-off in these establishments, I've already placed my view on record based on a case law supra. In so far as compensation for retrenchment and closure, sections 25F and 25FFF have to be strictly followed.
Coming to ALL OTHER INDUSTRIAL ESTABLISHMENTS EMPLOYING 01 to 99 workmen, no permission is required for lay-off/retrenchment/closure. But it is mandatory to pay compensations u/s 25-C,25-F and 25-FFF respectively. Besides, ONLY in case of closure those establishments having 50 and above but below 100 workmen on their rolls, it is mandatory that they have to send 60 days PRIOR notice to the Government u/s 25-FFA .
Here, by all OTHER ESTABLISHMENT, I mean EVERY ESTABLISHMENT employing less than 100 workmen other than those industrial establishments mentioned in sec.25-A of chapter V-A AND even THOSE ESTABLISHMENTS employing 100 and more workmen as well other than those as mentioned and defined in sec.25-K and 25-L respectively in chapter V-B of the ID Act,1947.
Regarding chapter V-B, I need not explain in detail about the aspects of lay-off, retrenchment and closure for the concerned provisions are very clear and self-explanatory. However, you should remember that sec.25-S of chapter V-B mandates the application of the general provisions of ss 25B,25D,25FF,25G,25H and 25J of chapter V-A.