Armed with smartphones, Colombians are taking on the local mozzies

IF YOU SEE a pothole, smell gas or step in water from a burst main, you can report the details online immediately. Smartphones mean that any concerned citizen can help keep a city’s infrastructure in proper repair—in theory. In practice, a nudge is sometimes required. And in the case of a project organised by Premise, a company in San Francisco that analyses geographical data, that nudge is financial.Premise, a recently formed firm, plans to make money by recruiting millions of observers. It will pay them each a fee to use their smartphones to gather whatever information is of interest to its customers about whichever country the observer happens to be in. The firm is now testing the idea with the Zika Citizen Network, a project that aims to find and stamp out mosquito-breeding sites in Colombia.