No smoking, no perfume and no mobile phone use - the list of rules at one newly built block of flats in Zurich is so long, it is a wonder anyone chooses to live there.
But for those who do, there is good reason. The 15 apartments have been designed specially for people who claim to have a condition known as "multiple chemical sensitivity".
Sufferers fall ill when exposed to the slightest waft of perfume or whiff of cleaning products.
Most of the residents in the building in the Leimbach area of the Swiss city say they also become weak and sick when near mobile phones or other wireless devices that emit radio waves or electromagnetic radiation.
While few doctors recognise the affliction, The Healthy Life and Living Foundation, which campaigns for greater recognition for MCS sufferers, convinced the Zurich authorities to provide land for the £4.1 million building. Christian Schifferle, 59, the head of the foundation, said he had suffered from MCS since being exposed to toxic fumes in his parents' furniture factory as a child. He has spent most of his adult life camped in a trailer in the pure air of the Swiss Alps. "All my life it has been like I was only half alive," he said.