Tokyo, June 30 : Ongoing concerns over a blackout in Tokyo were further raised on Thursday as a thermal power plant in northeast Japan was taken offline due to a technical glitch, as the mercury in the heatwave-hit capital soared to levels not seen in June in almost 150 years. The operator of the Nakoso coal- and oil-fired power plant in Fukushima prefecture, Joban Joint Power Co., said at around 3 a.m., the plant's No. 9 unit was shut down after a ventilator was found to be vibrating, reports Xinhua news agency. The plants operator said it aims to bring the plant back online and will restart supplying power to its service area, which covers a sizable expanse of eastern Japan including Tokyo, by Thursday evening. The Industry ministry said there was no imminent risk of a blackout even as demand for power in Tokyo surged as temperatures hit 36.4 degrees Celsius, the highest on record for June since 1875 when record-keeping began. The government for a fourth straight day has issued an advisory warning for Tokyo and surrounding areas of a possible power crunch if businesses and residents don't follow the required measures to conserve energy. Specifically, the Ministry warned that a surge in demand for air-conditioners amid the steering heat could lead to a power shortage. As wide-swathes of the country are experiencing a scorching heatwave, the Japan Meteorological Agency (JMA) and environment industry issued a "heatstroke alert," strongly advising people to stay hydrated and remove masks when outside in both eastern and western Japan. The JMA said that the mercury topped the 35 degrees Celsius in areas north of Tokyo, including Saitama and Gunma prefecture, while the Fire and Disaster Management Agency said 4,551 people were hospitalized for heatstroke or heat exhaustion nationwide for the week ended Sunday. The figure, it said, was quadruple that of heat-related illnesses logged the same period a year ago. /IANS