This slideshow explores the response of the city of London towards air pollution. London's mayor, Sadiq Khan, has aptly named air pollution one of the city's biggest threats. Public campaigns that emphasize eco-friendly transportation and the effect of air pollution on children's health have gained steam. Local city councils have formed groups dedicated to fighting illegal trash dumping. Posters and signs adorn buses, parks, and the city's main tourist attractions. But are these measures enough, or are they too little too late?