Pakistan Prime Minister Shehbaz Sharif has ordered an inquiry into the power outage in Pakistan that took place at around 7:34 am on Monday and left many cities including Karachi, Lahore, Quetta and Islamabad without electricity, Geo TV reported.

According to a statement from Pakistan’s Ministry of Energy, the national grid’s frequency dropped around 7:34 am, leading to a “widespread breakdown” in the electricity system. Additionally, it stated that Warsak was the starting point for the repair of grid stations. However, electricity has still not been fully restored nationwide, which is hindering companies and the daily lives of more than 220 million people.

The outage lasted for more than 16 hours, especially when temperatures were forecasted to fall to around 4 degrees Celsius (39°F) in Islamabad and 8 degrees Celsius (46°F) in Karachi, according to Geo TV.

The blackout, which Energy Minister Khurram Dastagir claimed was caused by a power surge, is the second significant grid breakdown in three months and adds to the nearly daily blackouts Pakistan’s population experiences.

The power outage occurred after a technical fault was reported in the transmission line from Guddu to Quetta, causing the reduction of the power frequency from the optimum level, AAJ News reported citing sources.

Sources revealed that Sindh, Punjab, and Islamabad regions were impacted by the power breakdown. According to sources, the complete restoration of electricity might take time. It is the second power outage reported over the past four months in Pakistan which is currently dealing with the energy crisis and high energy costs.

Islamabad Electricity Supply Company (IESCO), which provides electricity to Islamabad, Rawalpindi, Attock, Jhelum, Chakwal and parts of Pakistan-occupied Kashmir (PoK) said that the power supply to 117 grid stations of its company has been suspended, as per the news report.

IESCO tweeted, “Power supply to 117 grid stations of ISCO has been suspended yet no clear reason has been given by the Region Control Center. ISCO management is in constant communication with the concerned authorities.”