An out of control bonfire in a field close to the A40 Western Avenue in Ruislip closed two lanes of the road on Tuesday evening (October 31) and led to long delays.
London Fire Brigade said 30 tonnes of waste caught fire in open land close to Western Avenue between the RAF Northolt and the Polish War Memorial.
A picture from a traffic camera at the scene showed white smoke billowing from a huge fire in a field and tailbacks on the westbound side of the A40.
Traffic chaos was caused by people slowing down to view the fire which reduced visibility in the area.
Six pumps were sent from Northolt, Southall, Ruislip and Hillingdon after the blaze broke out shortly after 5pm.
Congestion stretched back all the way from Westway to White City on the A40 and travel time was around 50 minutes for motorists.
Keep up to date with the latest news in west London via the free getwestlondon app.
You can set up your app to see all the latest news and events from your area, plus receive push notifications for breaking news.