JOHANNESBURG, Oct 11 (Reuters) - South African business confidence fell in September compared to August, as retail sales and manufacturing output declined, data showed on Monday. The South African Chamber of Commerce and Industry’s (SACCI) monthly business confidence index (BCI) was down to 91.0 in September from 91.9 in August. “Less retail sales volumes, lower manufacturing output and a decline in the real value of building plans passed were detrimental to the business climate in September 2021,” SACCI said in a statement. “Energy and water supply concerns and higher fuel prices were also of major contributors to a wary business outlook. Secure energy supply remains a crucial concern generally to the business community.” State power firm Eskom, which has been mired in a financial crisis, said last week it would extend scheduled power cuts until Thursday after a series of additional faults at its coal-fired power stations. The power cuts are making it harder for the economy, which suffered a steep contraction of 6.4% in 2020 due to the COVID-19 pandemic, to recover. Reporting by Olivia Kumwenda-Mtambo Editing by Alexander Winning Our Standards: The Thomson Reuters Trust Principles.