Even though I do not recommend anyone to drink tap water in India and the 18 years of my life I was born and brought up in Delhi, I had no idea that you could drink tap water in other countries. Fortunately, I know much more now.
Tap water in India is certainly filtered and chlorinated and all the other things one would expect in any other country. It is not potable though If you drink it, you will be putting yourself at a risk and the locals know this very well.
At home, we have a Reverse Osmosis system which we use to filter out the water more and make it drinkable. Depending on the location where you (and I mean extremely specific, for instance water in East Delhi and water in South Delhi is of completely different taste and salt levels) plan to visit, your nifty gadget might be useful, but I won't trust it for providing drinking water.
Almost everywhere in Delhi, people refrain from drinking tap water, even after some additional small filtration. I have had some instances where I or many others have used such small gadgets to filter out the water, but drinking this on a daily basis is certainly at your own risk.
Furthermore, even if this device can remove most of the unfiltered bacteria, it would certainly not provide a pleasant taste in most of Delhi at least. Water in Delhi for instance is quite salty and I would suggest sticking to mineral unless there is absolute necessity.
Mineral water is super cheap in India. A standard 1L bottle of mineral water will cost you about Rs. 15 ($0.25).