Delhi, India,

is the most polluted city in the world,

 according to the World Health Organisation, 

 industrial waste, diesel vehicles, power plants in the city, and crop burning in the neighbouring Haryana and Punjab regions, all contribute to poor air quality, when nitrogen oxides and volatile organic compounds, released by these activities, react with sunlight it creates smog – making the air dangerous to breathe, levels of carcinogenic pollutants in Delhi are currently ten times higher than those in Beijing,

 so will this idea work? Dubai-based architecture studio Znera, shortlisted here, has developed a concept for a network of 100-metre high towers that would absorb smog and clean Delhi's choking air, called The Smog Project, the proposal envisions a grid of towers that could absorb pollution from the atmosphere, with each building creating a 1.2 mile radius of semi-clean air, 

 in Znera's proposal filtration pods at the base of each tower would capture pollutants at the level where people breathe, and propellers at the top would circulate the cleaned air,

each tower, Znera claims, would produce 3.2 million cubic metres of clean air each day, to reduce pollution to moderate levels, bridges would connect the vertical air purifiers, which would be arranged in a hexagonal shape and placed at key points in the city, so if the idea works it could mean clean air for all major cities.