In this era, the power of the people starts to slightly diminish. Kings and the high class actively let materialistic ideals into their lives resulting of fulfiling THEIR desires instead of using their divine will. People forget spirituality and let materialistic desires grow. The result of this are wars and climate changes.
Despite that, Treta Yuga brought knowledge resulting in further understanding of the natural forces and the true nature of the universe.
Treta Yuga is the second cycle of life. Its 1,296,000 years long.