He became conscious of his mistake and repented for his pride. There and then his city stopped falling and till today remains suspended in the atmosphere. His city has thus become a mirage and an illusion and is known as Harchandauri or Gandharva Nagari. It may be called a Utopia or imaginary creation, which is visualised in desert areas because of mistiness. It appears as a sheet of water, often inverted or distorted, caused by atmospheric refraction by hot air. See : Gandharva Nagari
References :
1. Kohli, Surindar Singh (ed), Dictionary of Mythological References in Guru Granth Sahib, 1993