There will soon be more trees than people in the city of Milan. Mayor Giuseppe “Beppe” Sala has embarked on an ambitious plan to plant 3 million trees in the Italian city—population 1.3 million—better known for industry than natural wonders.

For the last year and a half, the city of Milan has been working with Bloomberg Associates, the pro bono, a not-for-profit consultancy established by Michael Bloomberg with the goal of helping cities around the world. They work with local governments on disciplines like marketing, municipal integrity, sustainability, cultural asset management, urban planning, media, digital, tech, transportation, and social services. In Milan, the relationship covers about two-thirds of those disciplines, including the creation of new public plazas. That’s where the trees come in.

Planting 3 million trees by 2030 will help cool neighborhoods, improve air quality, and enhance public spaces. It’s all part of his master plan to green the city, greatly expanding from the 15,000 or so trees that the Comune di Milano traditionally plants each year. While trees have historically been primarily located in parks, in courtyards, and on private property, the plan devised by Mayor Sala and Bloomberg Associates accelerates the strategic planting of trees to focus on the hottest neighborhoods (hottest as in temperature, not real estate).

To accurately target those spots, they used satellite imagery to create a detailed heatmap, which identifies the hottest parts of the city at a granular level. Their tree-planting efforts now target those hot places, particularly the so-called “gray” parts of the public sphere, like streets, sidewalks, parking lots, and leftover paved spaces. Milan’s quest to plant more trees falls in line with wider efforts around the world to make cities more livable through the power of greenery.