By Somini Sengupta and Nadja Popovich
At a time when most of humanity lives in cities, where do cars belong — especially the old, polluting ones that make city air foul for people to breathe?
That question has vexed city officials across the world. Many are trying a variety of measures to reimagine the role of automobiles, the machines that forever changed how people move.
The immediate motivation is clear: City dwellers want cleaner, healthier air and less traffic. The long-term payoffs can be big: Curbing transportation emissions, which account for nearly a fourth of all greenhouse gases, is vital to staving off climate catastrophes.
And so, cities, which account for a large majority of global emissions, are dangling both carrots and sticks to persuade their residents to get out of their cars — or into cleaner ones.
Will it work? The last two times an odd-even measure was tried, it improved the air a bit, according to a study by the University of Chicago. But it was a temporary gain, and the city’s air remains extremely hazardous for the approximately 20 million people who live there.