Bulgaria`s executive environmental agency has raised Friday a second alert in eight days over high concentration of sulphur dioxide in the air over the central Bulgarian town of Galabovo. The pollution monitoring system in the town detected levels of the chemical substance considerably exceeding the threshold allowed. The output of the two nearby power stations and the power distribution factory is the reason for the pollution again, local environmental authorities commented. The operators in the thermal power plant complex Maritza -Iztok have already been ordered to reduce the power and to use coal with lower sulphur content. Galabovo citizens report that toxic pollution high above legal levels is often detected in the smog-covered town.