Related Clues:

• It is lowered for landing
• Dilute at 13's level of verticality
• 13 across person affected claims dazzling
• Groan endlessly in Suffolk river - it's related to sea level
• Visibility hamperer
• Reason for a flight delay
• Cloud near the ground
• Hazy state
• Horror film effect
• Weather for low beams
• Flight delayer, at times
• Coastline obscurer
• Hindrance to navigation
• Pea soup, e.g
• Film noir weather condition