All of south Mumbai and parts of central Mumbai are without power today after a unit of Tata Power tripped. The power outage, which started at about 9:45 a.m., has been partially restored in some areas. The Brihanmumbai Electricity Supply and Transport (BEST), which supplies electricity to the island city attributed it to a trip in Tata Power's Unit No. 5, which provides about 500 MW of power to south and central Mumbai, which are home to some of India's largest corporate houses. In a statement released in the afternoon, Tata Power said the power supply was affected due to tripping of Unit #5 of Trombay Power Station. "This tripping has resulted in load reduction of Parel, Mahalaxmi, Dharavi, Chembur and Grant Road area of Mumbai to control loading on 220Kv Khargar - Nerul – Sonkar - Trombay tie line," the company said, adding that it was working on an early resolution. Reliance Power, which also takes electricity from Tata and sells it to some Mumbai areas, tweeted that Tata Power has imposed rotational load shedding in Chembur, Bandra, Kurla, Santa Cruz, Ghatkopar, Tikar Nagar, Vikhroli, Saki Naka and Juhu. IMPORTANT: Power restoration information: 02- Sept 2014 pic.twitter.com/KvFcghXuMg — Reliance Energy (@Reliance_Energy) September 2, 2014 Several people are reportedly stuck in high-rises after elevators shut down because of a lack of backup power supply or generators. In a tweet, Anand Mahindra, chairman of the Mahindra group, said the power cut was likely because of a coal shortage. Mahindra Towers in Worli, which houses the corporate offices of the group, was also without power. Dark office in Mumbai. Lights out in the whole area. The coal crisis is beginning to literally show its dark side. A threat to the India story — anand mahindra (@anandmahindra) September 2, 2014 (For the latest developments on the Mumbai power cuts, follow us on Twitter @bsindia)