Source : Bhagavad Gita
“Triḿśad viḿśati varṣāṇi paramāyuḥ kalau nṛṇām,” - The maximum duration of life for human beings in Kali Yuga will become 50 years.
“Na rakshishyanti manujah sthavirau pitarav api,” - Men will no longer protect their elderly parents.
“Kalau kakinike ‘py arthe vigrihya tyakta-sauhridah tyakshyanti ca priyan pranan hanishyanti svakan api,” - In Kali-yuga men will develop a hatred for each other even over a few coins. Giving up all friendly relations, they will be ready to lose their own lives and kill even their own relatives.
“Sudrah pratigrahishyanti tapo-veshopajivinah dharmam vakshyanty adharma-jna adhiruhyottamasanam,” - Uncultured men will accept charity on behalf of the Lord and will earn their livelihood by making a show of austerity and wearing a mendicant’s dress. Those who know nothing about religion will mount a high seat and presume to speak on religious principles.
“Patim tyakshyanti nirdravyam bhritya apy akhilottamam bhrityam vipannam patayah kaulam gas capayasvinih,” - Servants will abandon a master who has lost his wealth, even if that master is a saintly person of exemplary character. Masters will abandon an incapacitated servant, even if that servant has been in the family for generations. Cows will be abandoned or killed when they stop giving milk.
“Dasyutkrishta janapada vedah pashanda-dushitah rajanas ca praja-bhakshah sisnodara-para dvijah,” - Cities will be dominated by thieves, the Vedas will be contaminated by speculative interpretations of atheists, political leaders will virtually consume the citizens, and the so-called priests and intellectuals will be devotees of their bellies and genitals.
Apart from mentioned in Bhagavada Gita, few other prophecies were made by religious experts of those times, which included: Thieves will become kings, and kings will be the thieves. The rulers will confiscate property and use it badly. They will cease to protect the people. Base men who have gained a certain amount of learning (without having the virtues necessary for its use) will be esteemed as sages.
Fetuses will be killed in the wombs of their mothers. People will prefer to choose false ideas. No one will be able to trust anyone else. People suffering from hunger and fear will take refuge in 'underground shelters'.
Young girls will do trade in their virginity. The god of rain will be inconsistent in the distribution of the rains. And, the shopkeepers will run dishonest businesses. Everyone will use hard and vulgar language. Men will devote themselves to earning money; the richest will hold power.
How will the world end?
The one who has taken birth, will remain forever in fear of death. So, to say this world too, one day see its end. End of this world or Pralaya, according to Puranas is of three kind: Naimittka- induced; Prakrita- natural; Atyantika- immediate.
This destruction will start with an underwater explosion that will take place somewhere in the southern ocean. It will be proceeded by a hundred year drought during, which the people who are not robust will perish. The seas, the rivers, the mountain streams, and the underground streams will be drained. Twelve suns will cause the seas to evaporate. Fed by this water, seven suns will form which will reduce the three worlds to ashes; the earth will become hard like a turtle's shell.