@User I tried the SRAMs in my design, eight 1KB SRAMS. This time I put the routing blockages on the whole SRAM of met1/2/3/4. Surprisingly all 400 something violations of huge metalX are gone now. If I don't put the routing blockages, the router still sees the blockages since it does not route over the SRAM but does not treat the blockages as huge metalX However as soon as I put the routing blockages, it seems now the router sees it as huge metalX.