For decades, the Mexican authorities have sacrificed a rural valley to flush away the capital’s waste and power the economy. Now, local communities are paying for that decision — often with peoples’ lives.

Did some of the season’s dependable pleasures — sunshine, lake vacations, time spent outdoors — feel newly in limbo this year? Blame climate change.

Six employees at Frankfurt Airport were infected this summer, according to German health officials and the airport’s operator. Four recovered.