Ayodhya is being decorated in the 'Treta Yug' theme for Ram Temple consecration ceremony as it's believed that Lord Ram was born in 'Treta Yug'. In Hinduism, 'Treta Yug' is the second of the four yugas. 'Treta' means a collection of three things in Sanskrit, and the 'yug' got the name due to three avatars of Lord Vishnu.