Water Supply issues a formal retraction in relation to the above article by Azubuike S. Ekwere et al. The publisher issues this retraction due to concerns over the originality of the authors’ work.

© 2021 The Authors
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).