Section 7. Effect of service of notice

From and after the service upon a defaulter to the notice of a certificate under section 6- (a) any private transfer or delivery of any immovable property of the defaulter situated within the local limits of the jurisdiction of the Collector issuing the notice or of any interest in any such property shall be void against any claim enforceable in execution of the certificate, and (b) the amount due from time to time in respect of the certificate shall be a charge upon the immovable property of the defaulter, wherever situated, to which every other charge created subsequently to the service of the said notice shall he postponed.