Removed Google Apps system app, now the device wouldn't boot
Reflash the Android One OS by booting into recovery. 

First get into the bootloader:

1) Power off your device and wait 4-5 seconds after lights go off.

2) Press and hold Power + Volume Up button together for a few seconds and then release the buttons as soon as you see the boot menu screen

3) Boot into recovery. Flash the Original ROM using TWRP or stock recovery