Indian waters are very, very polluted. And the pipes are in bad shape, so when the rain season arrives, a lot of dirty stuff get inside.
I drink a little bit of public water in asia or africa from time to time because I'm lazy. 99% of the time it's fine. But when it's not, it's heavy brown pants time, and I'm much, MUCH more tolerant than the average white guy when it comes to food poisoning because I traveled so much. In some countries (E.G venezuala), you can get amoebas out of it. And it's really annoying.
So basically yes, bottled water (and check the seal), or soda.
In some countries (e.g mali, sri lanka), they have water pockets, basically small plastic "balloons" of water than you bite then drink from. It uses less plastic than bottles, but yeah, it still finds it's way into the sea.