SGB pledging at zerodha

does SGB become eligible for pledging immediately after i purchase it or it has some cooling off period ? @mohitmehra @MohammedFaisal and does all SGB series qualify for pledging?

If an SGB is listed here, you can pledge it after it is available in your demat holdings. It takes T+1 days for the SGBs to be settled to your demat account after buying. On the T+2 day, you can place your pledge instruction on Console.

how much time does it take for new SGB series to come into pledging list @mohitmehra

This depends on the Clearing Corporation, the update their list of approved securities once per month.