Stefano Boeri Architetti
A rendering of a Nanjing Green Tower in China.
The $4, which uses a scale from 0 to 500 (with higher numbers indicating worse pollution), rates Nanjing's air quality as $4 - a level considered $4 for the public, especially those with respiratory disease.
The Italian design firm $4 believes that building towers covered in plants could help the city reduce its pollution. The company recently $4 that it will build two skyscrapers that will hold a total of 1,100 trees and 2,500 cascading shrubs on their rooftops and balconies.
Construction on the buildings, called the Nanjing Green Towers, began in early 2017 and is set to wrap up next year. The design will be similar to that of a $4 that Boeri designed in Milan. $4 in Lausanne, Switzerland will follow a similar plan and is expected to open by early 2018.
Though only two forest-like towers are currently underway, Boeri's ultimate goal is to create an entire "$4" in Nanjing and other Chinese cities.
Take a look at the plans below.