removing adware from Intex Aqua 4G Strong mobile phone

The Intex Aqua 4G Strong mobile phone running Android 5.1 which I had purchased to try out Reliance Jio had annoying adware and bloatware in the firmware. I uninstalled as many as I could, but some of them could not be uninstalled. I tried preventing notifications from them by long press on the notification to pull up the app's notification settings, and unchecking notifications from those apps. But still, on every restart, some app would try to install UCNews etc from outside Google Play store, and would be blocked by the security setting to Not Allow Apps from outside the Play store.

Finally thought I should get rid of this malware / adware.

1. Installed and ran Malwarebytes Anti-Malware app.
2. It identified the Malware as two apps, with the path to the apks being in the /system/ folder.
   
3. Since the apps were masquerading as System apps, they could not be uninstalled except as Root. So, installed Kingroot via the XDA developers forum to root the device. 
4. Ran Root Checker Basic to check for root - done. 
5. Installed Root Browser.
6. When running Root Browser, it asks if it can install some utilities. Said yes, it installed busybox tools. These are necessary to remount the volume as rw, and remove from system folder.
7. Navigated to /system/apps and removed the folders containing malware.
8. Ran Malwarebytes again to check that those were removed.
9. Removed Kingroot through its uninstall option.
10. Checked that root is now disabled.
11. Removed Root Checker.
12. Checked again with Malwarebytes that all is well. Done. 

Edit - this saga continues in another post here.