Police reduced speed limits on several motorways as fog returned for a second consecutive day in Abu Dhabi.
The murky weather affected the capital inland near the border with Saudi Arabia and a section stretching from Al Wathba to Sweihan.
Forecasters at the National Centre of Meteorology issued an alert and speed limits were reduced to 80kph on some roads as visibility fell below 1,000 metres.
The fog is expected to lift by 9am. A partly sunny day will follow.
There will be a slight fall in temperatures, with highs of 31°C on the coast and 33°C inland.
Humidity will return again overnight and early on Thursday, raising the risk of further fog in some areas inland.
Winds will be light to moderate and freshening during the day, especially over the sea where conditions will be rough in the Arabian Gulf and slight in the Gulf of Oman.