Milan city council has decreed a traffic block throughout the province for Euro-3 diesel vehicles without fine particle filters, after atmospheric sampling showed a rise in pollution.
The ban will remain in place until three consecutive days have passed with pollution levels back below the danger limit.
Private vehicles in this category may not run between 08.30 and 18.00, and commercial vehicles between 07.30 and 10.00. This block is in addition to any other traffic limitations already in effect.
Central heating will also be limited, with the indoor temperature down one degree to 19°C, and the daily operation of heating down from 14 to 12 hours daily. Shopkeepers have also been forbidden to leave doors open for pedestrian traffic.