Aging power distribution equipment is blamed for another electricity blackout that hit Moscow in less than a month. A tree fell on the power lines of one of the substations, causing the station's old equipment to short the grid.
The last blackout struck half of Moscow on May 25, less than a month ago, stranding nearly 20 million people in the subway and more than a thousand in dark, hot elevators. Health of more than four millions people was affected.
During Tuesday's blackout, only trolleybus and streetcar routes were affected. Officials are investigating the 3 50's-era power stations which seemed to have served the capital then with plenty of electricity.