Aeon of extreme miseries- That part (spoke) of the time-wheel, during which there prevails extreme miseries;
it is the last (sixth) aeon of the Avasarpiṇī (descending half of the time-wheel) and the first aeon of the Utsarpiṇī (ascending half of the time-wheel).
dusthu samā dussamā - duhkhartlpā atyantam dussamā dussama-dussamā.
(Sthā 1.133 Vṛ Pa 25)
ekkavīsam vāsasahassāim kālo dūsama-dūsamā.
(Bhaga 6.13)