Jain cosmology divides the worldly cycle of time (kalpakāla) in two parts or half-cycles (kāla) – ascending (utsarpiṇī) and descending (avasarpiṇī).
Avasarpiṇī is the descending half of the cosmic time cycle in Jainism and the one in which the world is said to be at present. According to Jain texts the Avasarpiṇī is marked by a decline in goodness and religion.
The ascending half of the cycle is called utsarpiṇī, which is marked by the ascent of goodness and religion.
During the ascending period (utsarpiṇī) of the half-cycle (kāla), in the regions of Bharata and Airāvata, there is the all-round increase in age, strength, stature and happiness of the living beings, while during the descending period (avasarpiṇī) of the half-cycle, there is the all-round deterioration. Each half-cycle is further divided into six periods of time.