Environmental alert reactivated in Mexico City; driving restrictions return just 20 hours after being lifted Environmental alert reactivated in Mexico City; driving restrictions return just 20 ho... High levels of ozone pollution prompted capital authorities to reinstate the alert on Thursday, less than a day after the previous warning was lifted.

		Environmental alert reactivated in Mexico City; driving restrictions return just 20 ho...   High levels of ozone pollution prompted capital authorities to reinstate the alert on Thursday, less than a day after the previous warning was lifted.