I just started facing this issue with the iOS 10 GM release. I received an email saying:
To process your delivery, the following issues must be corrected:
This app attempts to access privacy-sensitive data without a usage description. The app's Info.plist must contain an NSCameraUsageDescription key with a string value explaining to the user how the app uses this data.
Once the required corrections have been made, you can then redeliver the corrected binary.
The App Store team
Here's a link to a complete workaround from Google: https://groups.google.com/d/msg/google-admob-ads-sdk/UmeVUDrcDaw/HIXR0kjUAgAJ
More info at that link, but TL;DR version is you have to add three items to your plist:
<key>NSCalendarsUsageDescription</key> <string>Advertisement would like to create a calendar event.</string> <key>NSPhotoLibraryUsageDescription</key> <string>Advertisement would like to store a photo.</string> <key>NSBluetoothPeripheralUsageDescription</key> <string>Advertisement would like to use bluetooth.</string>