Possible Clues:

• Line on map, one originally standing on counter
• Front line summits of Sabalan, Oshtorankuh, Bazman, Alam-Kuh in Iran
• Line connecting points on a weather chart
• Sign of pressure thus internalised by current staff
• I do well to conceal black line on map
• Pressure line from one's pub carrying oxygen
• Evidence of pressure therefore in island pub
• First from optic in one's pub -- an indication of pressure?
• Line on a map is around bar
• One's no obstacle in the meteorologist's line