We saw them before we noticed the fragrance. People were carrying sprigs of a plant with tiny white flowers. I had not seen them before - but have since learned that they do not grow anywhere but in Asia. The Japanese teachers speak highly of this fragrant shrub. There are huge hedges of this evergreen plant which has the tiny flowers at the beginning of winter.
Initially we did not notice the frangrance of the bushes here as apparently the plants here do not have as strong a fragrance as in other places. Perhaps it is because they do not get much sun, I do not know, but we have been able to detect a pleasant fragrance from the plants, but not as strong as some folk describe.
In the bus, the bus driver will have a sprig of it on the dashboard and people take sprigs of it with them. Perhaps picking it from hedges in the street I do not know.
In Hangzhou there is a special event in the Botanical Gardens, and if you click here you will see a much better photo of the flowers.