Sahih Bukhari Volume 006, Book 060, Hadith Number 044.
Narrated By Ibn 'Abbas : 'Ukaz, Mijanna and Dhul-Majaz were markets during the Pre-Islamic Period. They (i.e. Muslims) considered it a sin to trade there during the Hajj time (i.e. season), so this Verse was revealed: "There is no harm for you if you seek of the Bounty of your Lord during the Hajj season." (2.198)