Harrison's enduring fantasy sequence concerning the fictitious city of Viriconium consists of three novels and various short stories and novels written between 1971 and 1984. Viriconium is known as the Pastel City. Both universal and particular, the city has a shifting topography and history, and is sometimes known by names such as 'Uroconium'.  The first book, The Pastel City (1971), presents a civilization in decline where medieval social patterns clash with the advanced technology and superscience energy weapons that the citizens of the city know how to use but have forgotten how to engineer. The more complex second novel is A Storm of Wings (1982). It is set eighty years later than The Pastel City. and stylistically it is far denser and more elaborate. A race of intelligent insects is invading Earth as human interest in survival wanes. Harrison brilliantly depicts the workings of civilization on the verge of collapse and the heroic efforts of individuals to help it sustain itself a little longer.  The third novel, In Viriconium (1982) (US title: The Floating Gods), was nominated for the Guardian Fiction Prize during 1982. It is a moody portrait of artistic subcultures in a city beset by a mysterious plague. Where the previous books in the series held some sword and sorcery elements, In Viriconium goes beyond black humour into a coma of despair.  The short story "A Young Man's Journey to Viriconium" (1985; later retitled "A Young Man's Journey to London") is set in our world. It explains that Viriconium can be visited via a mirror in a bathroom in a cafe in England.

Answer this question "what was viriconium about?" by extracting the answer from the text above.
It is a moody portrait of artistic subcultures in a city beset by a mysterious plague.