The 21st annual seminar on Islamic banking kicked off in Tehran on Saturday. With the theme of ""Usury-free Banking, Opportunities and Challenges"", the two-day event is aimed to explore avenues for removing hurdles on the way of promoting Islamic banking. Finance and Economic Affairs Minister Shamseddin Hosseini and Central Bank Governor Mahmoud Bahmani delivered speeches on the first day of the seminar, the Islamic Republic of Iran Broadcasting reported