There was a message on television where Regent Miguel Angel Mancera declared canceled all massive events in Mexico City. But it does not include a clear date on this cancellations. So it is very possible that the U2 concert will be canceled. It would only be necessary for the Rock Band to make a statement.
the local authorities are cancelling massive events like concerts and sports up until 29th. OCESA local promoter is having venues for concerts and sports checked for structural damages, they will give a status and if the events go on afterwards
I am sure the U2 management is already evaluating the situation because of the logistics of the show... it is on Oct 3 and 4, but the setup of the stage is previous days.