@Going234 thanks for the article... unfortunately (or fortunately, depending on how you look at it), figures say otherwise. There seems to be no end to the number of people visiting -which is probably not a good thing. As later as two weeks ago, for example, the figures for the cruise passengers arriving in 2017 were published and there has been an increment on the frequency and number of passengers, consolidating, by a long shot, the city as the main cruise port in the south of Europe; traffic at the airport has also increased reaching a new record of 47,4 million passengers in 2017 and making it the first airport in Europe in terms of annual growth.
And while Sagrada Familia, to put an example, has decreased visitors (in some 34,000) compared to last year, the annual figure stays at 4,5 million visitors, however, a few other (already popular) attractions have had double-digit growth.
Again, as someone pointed above, the city has 1.9 million residents (4.5 if considering the metro area, which comprises 36 cities and towns alongside Barcelona)... and receives nearly 18 million visitors (tourists included) every year. This is becoming indeed a problem for everybody: residents and tourists themselves. However, the trend continues to be, in general terms, "bullish", with nearly 47% repeating (up from 41% in 2013).
This is not a problem limited to Barcelona but to a very large number of other cities and towns here in Catalonia and also in many other countries. Has anyone been in say any of the picturesque towns in la Costa Brava in July? or in the Catalan Pyrenees during ski season?... it can be hellish. And tourism does not only refer to international visitors, but also to internal tourism here within Catalonia itself.
The issue is complex, with no easy solution in sight and, for the time being, no scheme anywhere in the world which suffers the same problem has been, let's say, successful. The City Hall in Barcelona and the Tourism Board -which are considered some of the best in the world regarding planning and strategy in this matter alongside others like Paris or London's- have been struggling with their counterparts around the world for a number of years trying to find a sustainable strategy which balances everybody's interests.... so far there have been only small successes.