It means that it was valid till the end of year 2010, otherwise there was no point of amending it. However, SRO 586/91 should be read in conjunction with SROs amending it like SRO 626(I)/ 91, 826(I)/1991, 1100(I)/1991, 1248(I)/2008, 1122(I)/1991, 1161(I)/2010, .
Though SRO 586/91 was issued under repealed Ordinance, however, SROs issued under s.50 of the repealed Ordinance are saved by s.239(12) of the new Ordinance of 2001