The Mayor of Delhi, Arti Mehra, has asked Union Urban Development Minister Jaipal Reddy to effect certain "vital' amendments to the Master Plan for Delhi-2021 on the basis of feedback from the various zones of the Municipal Corporation of Delhi. Ms. Mehra said on Thursday that though registration and payment of conversion charges for the shops under mixed-use regulations was to be done by June 30, most traders were unable to register themselves and pay the charges as they could not acquaint themselves with the provisions of the Master Plan.