There is no special treatment or compliances applicable to establishments which employ 50 employees other than having a certified standing orders. If you go further deep, you can see that when your number of employees becomes 50, the law relating to lay off ( the word used in reference to Industrial Disputes Act and not the word used in new generation HR to mean termination of employment) will become applicable and you can declare lay off if there is reasons like shortage of raw materials or accumulated stock or power shortage and while doing so the workers employed shall be paid only 50% of their wages. When your number of employees become 50, you need to inform the appropriate authority under the Industrial Disputes Act whenever you lay off some workers, whenever you find that there is redundancy and therefore, some of them (last employee joined in a particular department to be the first employee to be retrenched first) should be permanently retrenched or when you find that the unit is not viable and therefore, it should be closed. Obviously, when the number of employees become 100, in order to declare lay off or in order to retrench or close down or transfer the undertaking should require permission of the government.