Nightingale Valley is an ambitious housing development in New Ankh on the estuary plain Rimwards of Ankh-Morpork, nearby to the Sir Harry King Industrial Estate. It is assumed a responsible property development and speculation firm such as The CMOT Dibbler Practically Real Estate and Associates will have meticulously planned the new suburb using only the finest architects, civil engineers, builders, and building materials, and ensured at the very least that the new housing is situated on the upwind side of Sir Harry's complex.
As a former resident of the town of Reading, in Berkshire, UK, TP is bound to have been aware of the legendary "Whitley whiff", a delicately piquant aroma arising from the sewage works, reminiscent of rotting cabbage and fermenting beans. (Since their rebuild, those works no longer emit the same smell.) It is of course subject to speculation as to whether TP had this in mind.