KIEV, May 27 – Rivneazot, one of the largest chemical companies in Ukraine, has had to cease operation of its sewage treatment plants due to the full stoppage of natural gas deliveries to the company, a source at the company told Interfax-Ukraine on Tuesday.

The source said that the plant treated around 70% of the sewage in Rivne.

"The present situation is critical," he said.

The Rivneazot representative said that Rivne region head went to Kie to hold talks with the leadership of Naftogaz Ukrayiny to settle the issue of resumption of gas supplies to the company.