Severe water shortages in Iran in recent weeks have prompted electricity outages and even sparked deadly protests, but analysts say the underlying causes go back decades — and will rattle the country for much longer than this summer's drought.

Sadeq Ziaeian, director of Iran's National Drought Warning and Monitoring Center, said the country was facing one of its toughest rainfall seasons in 50 years.

In comments to the official IRNA agency and carried by the Tehran Times, he noted rainfall had dropped by nearly 50% in South Khorasan province this year compared to the long-term average and by as much as 80% in southeastern Sistan and Baluchistan province.