1. A method for identification of an activity performed by a subject, the method comprising: capturing movements of the subject in real-time using a sensing device, wherein the movements comprises n skeleton frames of the subject, and wherein each of the n skeleton frames represents data of N skeleton joints of the subject; ascertaining, by a processor, at least one action associated with the subject from a predefined set of actions, a plurality of actions from the predefined set of actions collectively forming at least one activity, wherein the ascertaining is based on captured movements of the subject and at least one predefined action rule, the at least one predefined action rule being based on context-free grammar (CFG) and being indicative of a sequence of actions for occurrence of the at least one activity; and determining, dynamically, by the processor, a current activity performed by the subject, based on the at least one action and an immediately preceding activity, using a non-deterministic push-down automata (NPDA) state machine.