InternationalTwo great green walls to stop global desertificationSònia SánchezandEduard Forroll09-05-2021
![A woman shielding herself from strong winds during a sandstorm on March 15, 2021 in Beijing. The Chinese capital and the northern part of the country received a sandstorm Monday that sent PM 2.5 and PM 10 air quality indexes soaring into the thousands and forced the cancellation of air quality.](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 9"%3E%3C/svg%3E)