Why Do Headlights Turn Yellow in Iran and the Gulf? Causes and Fixes
ChinKhoob · 2026-09-20
Short answer: modern headlight lenses are polycarbonate protected by a thin factory UV coat. Strong sun, summer heat (especially in southern Iran), dust and urban pollution wear that coat away; the plastic then oxidises and turns yellow. On cars parked outside, yellowing often starts after 3–5 years.
Main causes
- UV radiation breaks down the hard coat and then the polycarbonate (photo-oxidation).
- Heat above 45°C in Bandar Abbas, Ahvaz or Yazd, plus bulb heat, speeds up ageing.
- Dust and sand act like fine sandpaper and leave micro-scratches.
- Harsh cleaning — brush car washes, strong chemicals, dry-wiping a dusty lens.
- Stone chips crack the lens and let moisture in.
Three fixes
| Option | Lasts | Best for |
|---|---|---|
| Polishing | Often a few months in this climate | Light outer haze, no cracks |
| Lens replacement | Years, with a fresh UV coat | Deep yellowing, inner haze, cracks |
| New assembly | Years | Broken housing or failed electronics |
See polish vs lens replacement vs new headlight for costs.
Keeping new lenses clear
- Park in shade or use a car cover.
- Apply clear PPF or a UV ceramic coating.
- Rinse dust off with water before wiping.
- Avoid solvents and stiff brushes.