Matsyapurana 144.27

144.27

pūrṇe varṣasahasre dve paramāyustadā nṛṇām
niḥśeṣe dvāpare tasmiṃs tasya saṃdhyā tu pādataḥ //

In the Dvâpara age people were generally in trouble and there was an increase in greed ambition to trade and to possess worldly things tendency to fight and inability to realize principles, the obscurity of the Vedas and the Śâstras the destruction of the order of Varṇâśrama and the increase of lust and anger, the people, at this time, lived up to a period of 2,000 years when some time of Dvâpara was passed, then the Sandhyâ set in, in which period the dregs of the people are left Then the Sandhyâṃśa set in After this comes Kaliyuga At the end of Dvâpara and by the beginning of Kaliyuga, Kali became very strong—25 29