Air pollution is returning to China after a Covid-19 lockdown low, satellite images show. Meanwhile, a host of forward-thinking European cities are taking steps to avert a return “back to a dirty future”. Remote readings of the short-lived but harmful gas nitrogen dioxide picked up during late February and remained higher throughout March and April, though do not yet match a pre-lockdown high. The major sources of manmade NO₂ are combustion processes; heating, power generation, and engines in vehicles and ships, suggesting … Continue reading Air pollution returns to China