Letting the earth breathe. That is the ambition behind depaving — literally "de-paving" — the practice aimed at removing concrete and asphalt from urban areas, restoring the ground and making room for plants, trees and nature. It is not simply a matter of removing the surface layer: part of the previous soil is reinstated after the impermeable layers have been stripped away, the underlying ground is broken up and its profile restructured, so as to recover a genuine connection with the natural subsoil.

The idea originated as a civic initiative in the United States. The nonprofit Depave, which grew out of a neighbourhood association in Portland, Oregon, in 2008, worked with schools, social organisations and local businesses to carry out depaving projects throughout the city. Since then the movement has spread: the Depave Portland group has declared that it has depaved more than 70 car parks and removed approximately 14,000 square metres of pavement since it was founded in 2008.

The benefits of depaving

A study conducted in Aswan, Egypt, in a hot desert climate, measured the temperature above different ground materials and found marked differences. Average air temperatures ranged from 25.47 degrees above grass to 41.4 degrees above asphalt. Meanwhile, surface temperature reached its highest value above asphalt, at 50.27 degrees, and its lowest above grass, at 22.31 degrees.

The reason is straightforward. Asphalt is composed mainly of bitumen and dark aggregates, giving it a high volumetric heat capacity. This means that during the day it absorbs a large proportion of solar radiation, storing energy that it then releases into the air for hours after sunset. Asphalt thus contributes to the urban heat island effect. Depaving it — that is, removing and/or replacing it with soil or vegetation — increases the ground's capacity to absorb water, reducing the risk of urban flooding. Restoring permeable soil therefore acts on both fronts: summer heat and heavy rainfall, two phenomena made more frequent by the climate crisis. But the benefits recognised by local authorities and the scientific literature go further: a visible increase in tree cover and local biodiversity, and an improvement in air quality that cools neighbourhoods, especially in more disadvantaged areas that have historically had less access to green spaces and where the 3-30-300 rule is least respected.

The Italian cities that are depaving

In Italy, Genova is the first city to have formalised the practice within its urban planning framework. Mayor Silvia Salis has structurally embedded depaving in the city's Piano Urbanistico Comunale. The campaign begins in Cornigliano, a neighbourhood long marked by heavy industrial pressure, where concrete will be removed from the forecourt of Villa Bombrini to create a park of more than 13 hectares, funded by over 3 million euros from Regione Liguria and Società per Cornigliano. The measure extends beyond public interventions: property owners who direct urbanisation levies towards depaving works will be eligible for tax relief, provided they guarantee the maintenance of the green areas for at least ten years.

Then there is Milano, where depaving is already part of the city's "sponge city" strategy. Since 2022, the depaving strategy has made it possible to de-seal more than 50,000 square metres, of which more than 20,000 have become new green space and more than 30,000 have been replaced with permeable paving; the city administration has also identified 27 further new areas, in addition to the 27 sites currently under construction or already planned. One completed example is via Toce, in the Isola district, where 1,800 square metres of asphalt have given way to permeable surfaces, 720 square metres of new greenery and 35 new trees. Bologna is intervening on an even larger scale. Under the Bologna Verde programme, concrete and asphalt will be removed across more than 100,000 square metres of the city, starting with the former Ravone and former Casaralta sites. The programme includes increasing vegetation in the historic centre, boosting tree biomass, depaving urban areas and regenerating green spaces, with particular attention to areas characterised by critical levels of microclimatic vulnerability.

Finally, Roma, where depaving forms part of the "100 Parchi per Roma" programme. The most recent and concrete intervention is on via Ipponio, near Porta Metronia: the depaving works have enabled the removal of an asphalt layer, replaced with 960 square metres of stabilised paving and more than 1,000 square metres of green surfaces — an intervention that increases the soil's drainage capacity, improves the local microclimate and helps reduce the heat island effect. A second intervention is planned: a new park will be created at Piazzale Clodio, near viale Mazzini, through the depaving of the existing traffic island flowerbeds, which are currently partly asphalted and in a state of neglect.