That depends where in London you live. Hampstead Heath and Richmonds have very green areas (and are comparably easy to commute from). Western parts of the city also feel very green. Just the East is indeed very grey but that's because it was an industrial area until very recently.
And e.g. South Croydon (Purley, Kenley, Riddlesdown) or parts of Bromley.
There are large parts of the arc from South East London to South West London that have large areas with tree lined roads and woodland areas everywhere.
