A scheme allowing Madrid to restricting traffic in cases of high air pollution comes into force on the 27th February 2016. It replaces a similar scheme which had lower pollution threasholds.
The scheme limits access to roads inside the M30 on days of high pollution from six in the morning. There are 3 levels of pollution alert, “Notice”, “Warning” and “Alert”, with four phases of action to be taken.
Vehicles are allowed access on alternating days, depending on the vehicle number plate.
See the Madrid Odd and Even page for more details.