HARCHANDAURI You see only Harchandauri (Mirage), there is nothing permanent. (Asa M. 5, p. 461) When you see it carefully, the world is like Harchandauri (mirage), therefore get only the gain of the meditation on the Name. (Asa M. 5, p. 402) It is said that the king Hari Chand, son of Trishanku because of his great generosity and justice, was given a boon of going directly to heaven along with his subjects. When he left for heaven with his city and subjects, the sage Narada highly praised him for his works, which made him infatuated with pride. As soon as the ego welled up within him, instead of going upwards his city began to fall down.

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