That is difficult to answer because: what is stinking actually? It smelled different in a medieval town than nowaydays. Almost all houses had a fire place where wood was burnt. Poor people would burn turf (smells more). Besides for heating, the fires were meant for cooking as well. The blacksmith would forge on a coal fire. But there were no cars with stinking exhaust fumes. There were some things the medieval people thought smelled bad, like the leather tanners or the textile dyers. These were commanded to practice their activities at the edge of the cities. Urine was not thrown onto the streets but saved and sold to these people. Every house was supposed to have a secrete (toilet), they were usually put in the back garden. Some cities had already appointed garbage collectors by the 14th century. There were strict laws against polluting the city and its channels. Dirt was not allowed to be thrown onto the streets or in the channel. In the 14th century, in Dordrecht, a bleeder lady (a woman specialised in letting blood form people) was banned from the city for a period of 100 years and 1 day because she had thrown a bucket of blood into a channel. The channels needed to remain clean as the beer brewers used this water. Nobody wants to sit in the stench, not even medieval people.