GHG activities can have more than one Mapping ID e.g. Meter number and its unique code/GHG activity ID.
Because there can be more than one Mapping ID, a comma (',') will show up to separate the individual Mapping ID's (See Below). The Mapping ID will seem like one long unified ID however these are separate individual Mapping ID's for an activity - for example, a user can input 18933765333 or CorkWarehouseElectricityMeter for the Mapping ID in the spreadsheet for this activity which corresponds to the data which will be uploaded.
