What is the quality of the air we breathe in Italy? Legambiente asks this every year when drawing up the report Mal’Aria di città 2026, based on ARPA data. According to this year’s report, at the top of the ranking of the most polluted cities we have Palermo, followed by Milan, Naples and Ragusa. The 2025 data are nevertheless reassuring, with the Legambiente report showing a general improvement in Italian air quality. However, the projections for 2030 are worrying: many Italian cities are still above the standard established by the European Union.
But how is this ranking established? We see it in this article.
Palermo, Milan and Naples: the ranking according to Legambiente
Every year Legambiente tells us how we fare in the main cities in terms of air quality in its report Mal’Aria di città. The information reported in the report comes directly from the data collected in the various Italian regions by ARPA, i.e. the Regional Agency for Environmental Protection.
Like every year, a ranking of the “most polluted cities” is drawn up. Before we see it, let’s see what it means. The three parameters that are mainly monitored are the concentration of nitrogen, PM10 and PM2.5 in the air. When we talk about PM, we are talking about particulate matter, i.e. fine dust with a diameter equal to or less than 10 µm (micro, i.e. 10-6 m) in the case of PM10, with a diameter less than 2.5 µm in the case of PM2.5.
According to the regulations currently in force, the daily limit to be respected in the city is not to exceed 35 days in a year with PM10 levels exceeding 50 micrograms per cubic meter (for PM2.5 however there is no daily limit), while as regards the annual limit we are talking about an average of 40 micrograms per cubic meter for PM10, 25 micrograms per cubic meter for PM2.5.
The ranking drawn up by Legambiente in its annual report is based precisely on this, i.e. on the quantity of days in which the daily PM10 limits are exceeded. The first thing to say is that the data is improving: in 2025 there were “only” 13 provincial capitals that exceeded the 35-day limit, while in 2024 there were 24, 28 in 2023 and 29 in 2022.
So let’s see which are the 13 cities that have exceeded the daily PM10 limit for more than 35 days:
- in first place is Palermo with 89 days
- second is Milan with 66 days
- on the third step of the podium we have Naples with 54 days
followed in the ranking by Ragusa (61 days), Frosinone (55 days), Lodi and Monza (48 days), Cremona and Verona (44 days), Modena (40 days), Turin (39 days), Rovigo (37 days) and Venice (36 days).
In addition to the decrease in the number of cities that have exceeded the daily limit, another positive fact is that no capital has exceeded the annual limits for PM10, PM2.5 and nitrogen.
Limits for 2030 will be exceeded by many Italian cities: a worrying fact
Despite these positive signs, however, a great concern remains for Italy. Our country is in fact one of the areas most affected by pollution in Europe, and even if the data regarding pollution indicate a positive trend for our health, the projections are not so reassuring.
In fact, according to the standards established by the European Union for 2030, the daily limit to be respected for PM10 drops to 20 micrograms per cubic meter and for PM2.5 to 20 micrograms per cubic meter. According to projections based on data from the last 15 years, 33 Italian cities may not reach the target. Speaking of percentages, 53% of Italian capitals would appear not to be able to comply with the PM10 limit by 2030, the percentage rises to 73% regarding the limits on PM2.5, while 38% regarding the nitrogen value. In short, despite the improvements, what is worrying is the slowness with which Italian cities are reducing their pollution values from year to year.
To solve this problem, the Action Plan for Improving Air Quantity 2025-2027 provides for more stringent rules regarding heating appliances and the use of fossil biofuels, as well as greater controls and sanctions and greater citizen awareness. According to Legambiente, however, the action of the current Government, which has reduced the resources allocated to the Fund for improving air quality, is worrying.
