Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: Ukaz, Majannah and Dhu al-Majaz were markets in the time of Ignorance (Jahiliyyah). When Islam came, people regarded trading in them as sinful, so Allah Almighty revealed this verse: "There is no sin upon you if you seek the bounty of your Lord (in the seasons of Hajj)." [Surah al-Baqarah: 198]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8658