Types of strike: what are the conditions under which strikes are protected by law?

A strike is a collective and labor-intensive strike to defend professional demands.

There are so many types of strikes, like protest without working, pen down strike, Gherao, making surplus product to reduce the demand - like overworking as a protest, etc.

Strikes which are protect by law are the one's of those followed the due process of law as stipulated as per the labour laws applicable to them is like -- labour unions giving notice to the management for collective bargaining to resolve the issues amicably without therebeing any disturbance to prouction or going for strike. further things not resolved amicably through collective bargaining method, by giving notice period of strike to the management and the respective labour department authorities are the protected by laws. My 2 cents. Thanks.