Ok, I get it, so the upload speed is now throttled on the BSNL network for MTNL sims. The question I still have is whether anyone has ever got higher upload speeds on Mumbai MTNL network (not using mtnl sim on BSNL network).
I think it's got to do with MTNL server configuration. I get MTNL IP even on BSNL tower. So it doesn't matter even if my tower supports it, MTNL will never give me / anyone better upload speeds unless they improve their server, not just tower.