Mysterious obelisk

I have no idea what this is here for. It does not appear to have been properly finished, either. An 1895 picture of the Napier Bridge shows an obelisk at the north-eastern end of the bridge, but that looks like a pretty much completed structure. Maybe it was knocked down at some point, and an apology of a replacement was made.

But why am I thinking obelisks today? There is no connection between those indomitable Gauls who turn 50 today and the city of Chennai, save for the three years that Madras was under French rule. Yet, on behalf of all the Asterix / Obelix fans of Chennai, Bon Anniversaire!