When CAZ Tracker won't alert you
Last updated: 12 August 2026.
CAZ Tracker is a reminder, not a guarantee. There are many situations in which it will not alert you, and most of them are outside its control. You are shown this list in the app before you start, and asked to confirm you have read it. It is repeated here so you can read it before you install.
Your phone can stop the app
- Aeroplane mode, or the phone switched off or out of battery
- Battery saver / low power mode suspending background activity
- Android battery optimisation — Samsung, Xiaomi, Huawei and others close background apps aggressively
- Swiping the app away from your recent apps
- The system closing the app to free memory, or storage being full
- The phone restarting, and tracking not resuming until you next open the app
Permissions and notification settings
- Notifications turned off for CAZ Tracker in your phone's settings
- Location permission not set to “Allow all the time”
- Location services turned off for the whole phone
- Do Not Disturb, Focus, Silent or Bedtime mode hiding or muting the alert
Location isn't always available or exact
- No GPS signal — multi-storey car parks, tunnels, underground routes, indoors, or between tall buildings
- Poor-accuracy readings are deliberately discarded rather than acted on, to avoid false alarms
- GPS drift near a zone boundary can put you on the wrong side of it
How you've set the app up
- Quiet hours: anything detected between 11pm and 9am is held back until 9am
- Only the first alert for a zone each day — the charge is daily, so repeat entries are not alerted
- No alerts at all for a vehicle you have marked as compliant
- If you told us you drive a car, the app stays silent in Bath, Bradford and Sheffield, where cars are never charged — set the van/taxi/HGV switch if that is wrong
- The app trusts what you told it about your vehicle — it does not check your registration against the DVLA
Zone information can be out of date
- Boundaries come from council open data and may lag changes on the ground
- Newcastle and Portsmouth are not covered at all
- Charges, rules and exemptions change; amounts shown in the app may be out of date
Paying is your responsibility
Checking whether you owe a Clean Air Zone charge, and paying it on time, remains entirely your responsibility. CAZ Tracker is not affiliated with any council, Transport for London or the government, and cannot pay on your behalf. If in doubt, always check the official service.
Questions: [email protected]