Studio Symbiosis has designed Aũra air-purifying towers for Delhi, India, to help tackle the increasingly dangerous levels of pollution in the city.

Described by Studio Symbiosis as "breathing lungs of the city", the Aũra towers have tapered, twisting forms designed to draw in polluted air and expel it in a purified form.

The proposal responds to increasing levels of thick smog in Delhi that the studio says feels like "a gas chamber", which can be attributed to industrial waste, diesel vehicles, crop burning and power plants.

"Residents of Delhi are breathing about 25 times more toxic air than the permissible limit according to the World Health Organization guidelines, as on November 2019 according to India Today," explained Studio Symbiosis.

"Everyone who can afford to is buying home air purifiers but why is clean air becoming a luxury and only accessible to limited people?"

Studio Symbiosis has developed two different sizes of Aũra towers. The smallest measures 18 metres in height, while the larger tower is 60-metres-high.

The 60-metre-tall air tower relies on strong winds and is intended to be combined with several other towers to form a ring around the city's border that acts as a barrier to external pollution.

Meanwhile, the smaller towers act as a secondary system placed within the city's perimeter to maximise clean air during days when wind speeds are low and pollution is high.

Internally, both towers are divided into two vertically stacked chambers divided by a filtration system.

The top chamber is designed to draw in the polluted air through intake vents. Here, the air velocity is increased through compression so that it can be pushed downwards to pass through the central filtration system.

As it passes through the filtration system, it is cleaned before being expelled at the base of the tower through exhaust vents.

According to Studio Symbiosis, the 18-metre-high tower would be capable of cleaning 30 million cubic metres of air every day.

Both towers are complete with green planters that cover 60 to 70 per cent of their surface to produce oxygen.

The Aũra towers form part of a wider scheme by Studio Symbiosis to alleviate air pollution, called Aũra Hive.

This includes the proposal of Aũra Falcon Drones – a network of drones that slot into the walls of the towers that detach and move around the city to provide live updates of pollution levels.

Aũra Hive also includes the design of use of Aũra velocity – an air-purifying-attachment designed to be placed on top of cars that relies on vehicle aerodynamics.

"This ensures that part of the problem becomes a part of the solution," explained the studio. "The more these cars move in the city, the more they clean the city. It is a design of inclusion, rather exclusion."

Noida-based Studio Symbiosis is now planning the construction of the first 11 of the towers as part of Eco Park – an 890-acre park under development in Delhi that is set to become India's "biggest manmade biodiversity park".

Similar designs on Dezeen include The Smog Project by Dubai-based architecture studio Znera – a network of 100-metre-high towers that would absorb smog in Delhi – as well as Daan Roosegaarde's seven-metre-high Smog Free Towers.