Aeroplanes heading to Nigeria’s largest city, Lagos, are being redirected to other airports because of the seasonal harmattan winds, which carry dust from the Sahara that impairs visibility.
Lately a thick smog has been hanging over the city.
Aviation authorities say the winds are stronger than usual this year and for three days planes destined for Lagos’ Murtala Muhammed International Airport have been redirected either to the capital, Abuja, or to the Ghanaian capital, Accra.
The harmattan is a dry desert wind that blows south from the Sahara for several months - between November and March.
A pilot told the BBC that the Murtala Muhammed Airport did not have a working instrument landing system (ILS), the automatic landing system that helps planes land.
This means planes cannot land when there is poor visibility.
Thousands of passengers are stranded at the airport - and at other airports waiting to get to Lagos.