Iran has started implementing rolling power blackouts across the country as the Islamic republic struggles with a shortage of natural gas ahead of winter.

Two-hour daily outages will be enforced in Tehran, the capital city that is home to 9.5mn people, from Monday and will affect homes and businesses, local media reported. Several provinces were also hit by the power cuts on Sunday.

Iran is suffering from an energy supply crunch despite having the world’s third-largest oil reserves and second largest natural gas reserves. Years of under-investment in electricity generation and poor maintenance of existing infrastructure have resulted in recurrent power blackouts during summer, when hotter temperatures led to a surge in the use of air conditioning.