What is the standard voltage and current levels for an android battery?

First of all, I would like to thank everyone who helped me understanding what can be the problem exactly; I am posting it as an answer because this is what solved my issue.

The problem was neither with the charger nor with the USB cable. The real culprit was an extension cord which was offering very high resistance probably.

Since my socket is at a certain height, i was using an extension cord to extend my USB. I observed readings from both ends, keeping extension cord and then removing it. I found huge difference in the current ratings. It came as 230 mA and 770mA respectively.

Now, I am using a home made mobile holder while charging and removed the extension completely from the circuit. Everything seems to be working as expected.

Hope this helps someone else who is encountering same issues using extension cables.