According to @visit Abu Dhabi  there have been 100,000 people who have signed up for Coldplay's concert presale!! The amount of tickets available for the concert are only 50,000, that is HALF of the amount of people who have signed up for the presale! 

All of the cities in the tour are getting at least two nights, many of which are near each other. The Abu Dhabi concert is the only one in the entire MENA region.  While there is evidence that the demand is much higher than the tickets available, this is only if we are assuming that those who have signed up for the pre-sale are buying one ticket. It would make much more sense for there to be multiple nights, for example London alone is getting SIX NIGHTS!!