Wifi Automatically turning on in my Android (Sony Xperia Z)

Guys, I need help. I found that even if I turns of OFF wifi in my phone, it automatically turns on. Its very weird, if I want to use my mobile data connection, even then after a while I see that WIFI is auto turns on and using home network. It was not like this before, it started just few days ago or I noted few days back only. What is happening to my phone, is it infected by some bad application or compromised ?

I think you installed some application which needs your location every now and then. Just check most recent application you installed or also check the application you allowed to have location access.
Best try is to disable location access and then check if it automatically turns or not .