The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite detected hundreds of fires burning in central Africa on August 21, 2013. The fires are outlined in red. Most of the fires burn in grass or cropland which is obscured by the smoke in this image.
The location, widespread nature, and number of fires suggest that these fires were deliberately set to manage land. Farmers often use fire to return nutrients to the soil and to clear the ground of unwanted plants. While fire helps enhance crops and grasses for pasture, the fires also produce smoke that degrades air quality.
In Africa, the main growing season starts with the first rains in September in the south which would be the right timing for the agricultural burning that seems to be taking place since they are just clearing old fields to plant new crops in September. In addition to pollution produced by agricultural fires is the possibility of deforestation, erosion, nutrient loss, and possible extinction of species. If a particular area is the only one that holds a particular species, slashing and burning could result in extinction for that species.
Explore further: NASA image: Fires in West Africa