Pigeons have been derided as rats with wings and shooed away everywhere from window ledges to public squares.
But this past March, a flock of half a dozen pigeons, strapped with tiny backpacks, carrying pollution sensors, were set loose from a rooftop in London’s Brick Lane. One little bird also had a G.P.S. tracker.
The winged patrol will fly all over the capital and tweet back readings about air quality. The project’s goal is to raise awareness about dirty air.