Himachal Pradesh government has evolved a single window clearance mechanism for allowing film units to shoot in various parts of the state. Chief Minister P K Dhumal said yesterday that film units visit the state throughout the year and the single window clearance system would not only facilitate such activities but also boost tourism. He was inaugurating the five-day long exhibition organised by PHD Chamber of Commerce and Industry in Shimla. Dhumal said that Himachal had been allowed a 10-year tax holiday for opening and running hotels in tribal and remote areas with a view to give a boost to tourism activities in virgin and hitherto unexplored areas.