Will leafy walls tackle London's pollution problems?
Pollution in London is amongst the worst in Europe and, as I've mentioned before, the mayor and Transport for London (TfL) are trialling all kinds of new technology to get the levels down.
They are already using "dust suppressants" on Upper Thames Street to stick pollution to the road. Now we are getting Green Walls.
The Green Walls are specially designed to trap harmful particulate matter, known as PM10s.
TfL believes the walls will help at hotspots that regularly exceed EU legal limits.
Campaigners believe more needs to be done to deal with the cause of the pollution and reduce the amount of traffic.
The cost of the project is £5m from the Department of Transport, but will it work?