 At the same time, there has been a significant increase in the number of new citizens entering the area, who have started to work in the fledgling industries in the area; as can be seen from demographic trends, between 1861 and 1961, the population of San Giorgio quadrupled.Then, due to the various economic crises that followed in the decades of the 20th century, a new phase began that led to the closure of many companies with the consequent birth of many brownfield areas, many of which were recovered.According to , San Giorgio su Legnano is in Zone E with a rating of 2451 GR/G.