Two perplexing events occurred in Sofia over the course of the past several days - yellow stains on the ground and a strange odor in the air. The streets and balconies across Sofia were all covered with yellow dust Monday.

The most probable reason is winds coming in from Africa, stated meteorologist Petar Yankov. According to the official information presented by the Civil Protection Office, there is no data of increased radioactivity levels, and the Environmental Ministry announced that samples have been taken from the dust. The results will be announced later on Tuesday, as reported by Trud daily.

Alternatively, it is possible that the stains have been caused by the flower blossoms.

There has been similar yellow dust in the past and it was caused by pollen, the Regional Environmental Inspectorate stated.

Meanwhile, several signals have been received of a strong odour of sulphur and other poisons, submitted by people from the Sofia neighborhood Druzhba 2. Inspectors have visited the site but did not take any probes on account of the fact that there are no production facilities located nearby.

The source of the unpleasant odor still remains a mystery.