Analysis of information sources in references of the Wikipedia article "கலி யுகம்" in Tamil language version.
On the very day, and at the very moment the Lord [Krishna] left the earth, on that very day this Kali, the source of irreligiousness, (in this world), entered here.
The Parijata tree proceeded to heaven, and on the same day that Hari [Krishna] departed from the earth the dark-bodied Kali age descended.
Kali Yuga began on the day when Krsna passed on to heaven. Understand how it is calculated.
Kali Yuga had started on the very day when Krsna passed away.
It was on the day on which Krishna left the Earth and went to heaven that the Kali age, with time for its body set in.
The [Kali yuga] epoch arrived at ... was midnight of February 17/18 in 3102 BC according to the midnight (ardharatika) school, and the sunrise of February 18 (Friday) of the same year according to the sunrise (audayika) school.
