Eskom, which is considered South Africa’s biggest polluter, has said emissions of particulate matter that cause chronic respiratory disease are at their highest level in two decades.

This is due to the state power utility’s financial meltdown, which has seen it skip maintenance.

“The high emissions were mainly due to poor performance at power stations because of a lack of maintenance earlier in the year, which was exacerbated by the industrial action in June 2018,” the company said in its annual results presentation.

“Plans are in place to improve both particulate emissions and water usage.”

Air pollution is fast becoming a key issue in South Africa. Residential areas near Eskom’s coal-fired power stations have pollution levels that rival the most contaminated cities on the planet.

Environmental activists are suing the government over breaching the constitutional right to clean air because of emissions from Eskom and chemicals company Sasol.

The rise in pollution comes mainly came from the Kendal and Tutuka power plants. Poor quality coal also heightened emissions at three stations.

The company posted a record loss in the year ended March 31 and has more than R440bn in debt.