Grey to Green is a very simple idea that, once seen, makes you wonder how no one has thought of it before. It's essentially paving slabs with holes built into them.

Crazy paving. by Jamie Cable. 27 June 2014. iStock. IN GARDENS in London, hard surfaces and new buildings are replacing vegetation at the rate of two-and-a-half times the area of Hyde Park each year.

Paving slabs that suck pollution from the air are to be installed in the UK for the first time. The ground-breaking Noxer blocks, pioneered in traffic-choked Tokyo, will be trialled on the ...

I have for the past few months been following the debate on asphalt crossings, (Bitumen blight', April 12).