"The total volume of dam reservoirs in Tehran province is currently 170 million cubic metres," said Rama Habibi, an official with the Tehran Regional Water Company.

"This amount was 381 million cubic metres during the same period of the last water year," he added, according to the state news agency IRNA.

"The Latyan, Amir Kabir, Lar, Mamloo and Taleqan dams show a significant decrease in the volume of incoming water compared to the long-term period."

The figures were revealed as the country continues to suffer its most severe drought since records began six decades ago and its driest autumn in years.

"The third month of the autumn season began with only 1.7 millimetres of precipitation, and Tehran province has faced a 96.5 percent decrease compared to the same period last year," Habibi said.

Iranian authorities have also launched cloud seeding operations to induce rainfall and resorted to cutting off water supplies periodically to manage consumption.

Citizens held prayers for rain in several different cities over the past several weeks.

Iran, a largely arid country, has for years suffered chronic dry spells and heat waves, which are expected to worsen with climate change.