How to flash stock ROM over ADB sideload
I finally was able to solve this problem, as Firelord said, adb sideload wasn't able to help in the case of this ROM. And SP Flash tool turns out to be the best for MediaTek devices.  

Most of the ROMs (Stock or Custom) are available on http://www.needrom.com, so I would recommend it to others for downloading ROMS. However, the website requires signing up in order to download ROMs.

SP Flash Tool, in order to work, needs the following things:


A formatted SD Card in your Mobile Device
Battery to be re-inserted after removing (within 10-15 seconds)
Media Tek VCOM drivers to be installed in your PC. (Link: https://docs.google.com/uc?id=0B9srKhKuVIMnalFkV3EzWjVXdUE)
A scatter-based ROM for your device.



  Note: SP Flash tool needs to be Run as Administrator while using it.


A factory data reset from the Recovery mode is advisable after successful flashing.