Our photo uploads give scientists billions of eyes on the world

IN 2015, humanity put 2 or 3 trillion photographs on the internet. Now, researchers are tapping into this vein of information, studying photos in bulk to give us fresh insights into our lives and our cities. In Singapore, a project called AirTick is aiming to use these photos to get a handle on air pollution. This is a serious problem in south and east Asia where schools and factories shut down when pollutants reach dangerous levels. The World Health Organization estimates that one in eight deaths worldwide are caused by air pollution.