Concept of Samsara in Hindu religion is of great importance and is tailored around idea of mundane existence. The word samsara is derived from the Sanskrit word samyak, meaning well and sar, meaning to move (transmigration or succession of births). The individual jiva (self) is actually Paramatman, the Absolute Being. As Paramatman is all pervasive and full, there is no movement for him. Consequently jiva also has no movement. But when he identifies himself with his intellect, which acts as his adjunct, jiva appears to move from one place to another.
Jiva first identifies himself with the intellect, and then through his intellect with his sense organs, and then with his gross body. He is under the influence of avidya (ignorance) and so is always pushed out from his gross body towards the various objects in the world. Being under the influence of the three gunas called – sattva, rajasand tamas, which are in the intellect, he develops raga (an attraction) and dvesha (dislike) for various objects with which he interacts. The interactions fetch him both good and bad results. These are not exhausted in one birth. Thus a series of births follow. There is no escaping the fruits of action all actions, good and bad. It is only by annihilating ignorance, which is the root cause of this vicious circle of births and deaths, one can hope to get out of it. Ignorance vanishes with the dawn of knowledge of the Absolute. Till such time as the individual self attains moksha (salvation), it has to wallow in the state called samsara.
The miseries that one gets in this samsara fall under three heads –adhyatmika (related to body), adibhautika (related to the elements), and adidaivika (accident in nature – literally pertaining to gods). This gross body itself is a source of misery, as all sorts of diseases and worries are felt through it alone. Some of the troubles, like the scorching heat of the sun, incessant rains, and chilly weather, etc cause problems to human beings. They are classified as adibhautika. There are some problems for which one may not know the reason at all. These problems may come from any direction without any trace of suspicion. As the visit him without any knowledge cause, they are called adhidaivika. Miseries cannot be completely avoided. Hence, the only method of annihilating them totally is by getting the knowledge of the Absolute, which will wipe away the root cause of these miseries, namely, avidya (ignorance). Four pathways to salvation are well known – jnana (knowledge), karma (action), bhakti (devotion) and yoga (physical and psychical perfection).
Source - Encyclopedia of Hinduism Volume IX - IHRF