Sub-Saharan Africa’s regulatory environment ranks amongst the least business friendly in the world. The difficulty of starting and operating businesses and the high tax burden are amongst the major conditions that make the regulatory environment hostile. This study examines how these business regulatory conditions explain the growing challenges in mitigating CO₂ emissions in the sub-region. For this purpose, data from 1997 to 2018 are used to analyse an extended environmental Kuznets curve (EKC) equation for thirty (30) Sub-Saharan African countries. The results of the Method of Moments Quantile Regression analysis show that the inverted U-shaped curve of the EKC hypothesis is statistically not valid across the entire quantile distributions. The impact of increasing tax burden on CO₂ emissions is positive and increases across the entire quantile distributions. Business regulatory efficiency has a negative (i.e. decreasing) impact on CO₂ emissions across the entire quantile distributions and shows a stronger impact in countries at the upper quantiles, such as in South Africa, Botswana, Gabon, and Nigeria. Conclusively, policy choices that seek to reduce tax burden on households and firms and foster greater economic freedom for businesses are needed to break the growing trend in Sub-Saharan Africa’s CO₂ emissions.

Discarding fly ash from a coal power plant into a dumpsite does not only contribute to deforestation and loss of productive land but also leads to contamination of air, soil, and groundwater. Therefore, fly ash should be managed properly to avoid the migration of contaminants. One management option is phytoremediation using adapted plants and as a prerequisite, there is a need to identify suitable plants that can be used for revegetation of fly ash dumpsites. To identify prospective plants, a survey was carried out by assessing the plants growing in Morupule B fly ash dumpsite based on their ability to accumulate heavy metals and their bioconcentration (BAF) and translocation factors (TF). Of the twenty-two-plant species growing in the fly ash dumpsite of Morupule B power plant station, N. glauca is a potential phytoextraction agent for Cu (TFCᵤ = 1.02; BAFCᵤ = 2.16) and Pb (TFPb = 1.38; BAFPb = 1.65); P. burchellii for Pb (TFPb = 1.61, BAFPb = 0.9) and Zn (TFZₙ = 1.35; BAFZₙ = 5.74); I. pes-tigridis for Pb (TFPb = 1.35; BAFPb = 1.56) and Zn (TFZₙ = 1.62; BAFZₙ = 7.43); A. pungens for Cr (TFCᵣ = 1.22; BAFCᵣ = 0.11), Cu (TFCᵤ = 2.18; BAFCᵤ = 1.14), and Zn (TFZₙ = 1.04; BAFZₙ = 1.44); E. hirta for Zn (TFZₙ = 1.54, BAFZₙ = 2.44); A. spinosus for Pb (TFPb = 1.29; BAFPb = 1.55); C. dactylon for Cu (TFCᵤ = 1.86; BAFCᵤ = 1.07) and Zn (TFZₙ = 1.00; BAFZₙ = 2.46); and D. aegyptium for Pb (TFPb = 1.19; BAFPb = 2.57). Other plants growing in the fly ash dumpsite are potential candidates for phytostabilization as they can tolerate a high concentration of metals and low essential nutrients. Also, different plant groups variably modified the pH, EC, OM, and exchangeable fractions of metals in the rhizosphere wherein grasses can increase the OM at higher rates, and it has a higher capacity to acidify and solubilize heavy metals in the rhizosphere leading to higher EC and available metals compared to other plant groups. Overall, the information presented is useful in identifying plants or their combinations for the phytoremediation of fly ash and other heavy metal-polluted environments.