Here’s a method you may want to try to block and remove annoying ads popups on official MIUI 8 Global ROM. This method was tested on Xiaomi Redmi Note 3 Pro Special Edition, but most probably will work as well on other phone models.
Delete or remove popup advertising on MIUI 8 Global ROM Redmi Note 3 Pro SE
You can find some ads in different applications, for example in “Security” > “Wipe”. The amount of ads are also depends on your device region settings.
There’re three apps that are responsible for advertising. So, basically to block / remove ads on MIUI 8 Global ROM, you would need to disable internet access for these 3 applications:
The most easy way is to root your device and then disable network access for the apps above. If you ain’t got root on your Xiaomi phone, then you can try using Adguard application from Google Play Store.
Also, keep in mind that unofficial localized MIUI roms usually doesn’t contain any ads.