Every time there's a lull in winds and rain to clean Milan's skies and the smog piles up over the city and hinterland, the full amount of Lombardia's pollution is suddenly revealed. If in winter the particulate counts go far higher as most central heating is from legacy diesel oil combustion.
I have workstayed in Milan many times and while not Bangkok levels, the pollution levels were stifling, only relieved when (extremely acid) rain would fall and temporarily rinse the air. Summer, while better from the heating being off, is also worse because of the intense heat buildup from hot weather radiating from the cement almost till dawn and the sun's interaction with the emissions, L.A. style.
Traveling on a 'pendolino' (short commuter trainride from city centre to suburbs and back) there haunted me for days as never elsewhere in Europe have I felt such a palpable sense of desolate doom as exhausted low food-chain workers (mostly POC) returned home in silence, body language of crumpled defeat, 1000 mile stares, the implicit acceptance and sadness of that knowledge parallel with the grimy light and sepia sorrow of the scene.
It was 20thC Dickensian, an Italian Ruhr valley.

Looking at European pollution maps the obvious immediate suspects, the big cities, Brussels, Paris and like stand out till you grok that a triangle between Piemonte, Lombardia, Veneto and Emilia-Romagna pumps out more pollution than anywhere else. The Italian Wuhan, iow.
The hotbed and stronghold of Italy's AFD party, the Lega di Salvini, whence come regular calls to secede from the 'lazy, parasitical' south (whose starving emigrés powered the North's workhouses during the golden years of Italian industrialisation), before Fiat jumped ship to the USA after sucking public bailout funds for years after Italy's boom hit reality's shoals. Alitalia is on a similar teat right now, huge payouts to heads of failed companies, who then fall upwards to helm other state/private shipwrecks.
Northern Italians have been so much wealthier than Southern counterparts since Alpine trade routes opening to North European markets supplanted the South's historical sources of maritime trade wealth that there are basically 2 Italy's now, and little love lost between them.
Northerners mostly vote C. right and hard right, like Republicans in the USA they hate central government because they only want to pay less taxes, Berlusconi's siren song. Southerners take free fish dinners and are slipped E50 to vote for whom the mob tell them to vote for, whoever accomodates their simbiosis, deals not ideals, party-agnostic, or don't bother voting at all, (understandably as it hasn't detectably improved their lot much).
This concentration of wealth in the north has much weakened any unity Italy enjoyed, sapping civic sense and national identity.

Perhaps this crisis will humble the hothead Salvini, whose 30% poll ratings make him the shoo-in next PM if Conte drops the ball and Italy goes to new elections.
Tellingly Salvini carbon-copied Trump, Bolsonaro, Johnson and Rutte in his initial economy-trumps-human collateral damage and similarly has U-turned and is now rabidly baying for tighter control, tanks in the street etc.
Renzi suffers equally from media attention deficit syndrome (and love for Berlusconismo) and so his perennially polemic yappings punctuate and pollute the political discourse further even than when he was PM. His job is to outyap his own ovious-to-all-but-him political irrelevance and together with Salvini stir shit to undermine Conte, whose continued popularity infuriates both of them. The Pekinese and the Pitbull running maximum interference to Conte's smoothly calming leadership so far in this crisis.
In an Italian political climate that favours hysteria and hype Conte stands out for dignified aplomb. After some initial message fumbling 3 weeks ago he has kept his head commendably during this epic crisis, treading the finest of political lines between health and wealth calmly and seriously.
For which in these saddest of times I and many, many others here am incredibly grateful.

(Especially watching how other state leaders are comporting themselves evem after so much time and warning.)

'The history of public debt is full of irony. It rarely follows our ideas of order and justice.' Thomas Piketty