Srimad-Bhagavatam: Canto 12 - Chapter 1 - Verse 30

Sanskrit:

यदा मायानृतं तन्द्रा निद्रा हिंसा विषादनम् ।शोकमोहौ भयं दैन्यं स कलिस्तामस: स्मृत: ॥ ३० ॥

ITRANS:

yadā māyānṛtaṁ tandrānidrā hiṁsā viṣādanamśoka-mohau bhayaṁ dainyaṁsa kalis tāmasaḥ smṛtaḥ

Translation:

When there is a predominance of cheating, lying, sloth, sleepiness, violence, depression, lamentation, bewilderment, fear and poverty, that age is Kali, the age of the mode of ignorance.

Purport:

In Kali-yuga, people are almost exclusively devoted to gross materialism, with hardly any affinity for self-realization.