Capital market regulator Sebi has set up a task force to review the risk management norms for national-level commodity bourses following the suspension of futures trading for castor seed on NCDEX. A source said that after recent developments witnessed in castor seed futures contracts, Sebi has established a task force to relook at the existing norms related to risk management, delivery mechanism, and other related issues. The task force has been asked to submit the report in three weeks. Based on the report, the risk management norms for national-level commodity derivatives exchanges will be further tightened.Meanwhile, Sebi has sought explanation from the exchange for suspending futures trade in castor seeds.