Fats and oil poured down the drains are being blamed for the smells affecting a Worcestershire town centre.
Engineers have been investigating complaints in Droitwich's High Street.
They now blame a build-up of fats, oils and grease, or FOGs, for the problems and have encouraged shopkeepers and food outlets to clean up their act.
Wychavon District Council environmental services manager, Geoff Carpenter, said firms have complied with requests to have waste taken away properly.
There were complaints about smells from shoppers and traders. He said: "The oils and fats were not helping."
He added that residents should stop pouring fats down sinks and businesses should arrange for professional collection of waste oils and fats.
They have been blamed for clogging town sewers and leading to the smell.
Subsidence was originally blamed for affecting the Victorian drainage system in the town before the FOGs were uncovered as the source of the smells.