Five sets of draft rules relating to registration, payments, returns and refunds under the Goods and Services Tax (GST) regime were approved by the GST Council here on Friday, Finance Minister Arun Jaitley said.Briefing media after the meeting here, Jaitley said the big task of GST rates, service tax assessments and compensation for the states remained yet unresolved and will be decided in the Council's next meeting on October 18-20. "Rules for registration, payments, returns, refunds approved by Council," Jaitley said adding, "rates would be the big item to be discussed in next meet. Discussion regarding service tax assessments, states' compensation will also continue in next meet."This was the second meeting of the Council, the first one was held on September 22.