Shenzhen held its first extensive blackout drill yesterday to prepare for typhoons and the region's persistent electricity shortages. More than 700,000 people participated in the three-hour exercise, during which authorities tested emergency plans at key locations such as hospitals, the stock exchange, subway stations, police stations, telecommunication centres and the airport. 'We have had many typhoons this year. There is a real danger of our power supply network getting damaged in a typhoon and causing extensive blackouts,' said an official from the city's electricity supply bureau. 'Shenzhen has over 10 million residents. We have one of the two stock exchange centres on the mainland, and we have the world's busiest border checkpoints. If we lose electricity, we must ensure there are viable plans to cope.' Apart from natural disasters, Shenzhen also faces possible power failure because of severe electricity shortages, which have reached new highs this year. The city increased its power generation capacity by 12 per cent from January to July, but many suburban areas must still ration electricity, according to Zhang Zhixian, a deputy director of the bureau. Mr Zhang said he feared the existing network would become overloaded, causing extensive blackouts. He said the bureau had invested 1.4 billion yuan to upgrade the city's power grid. Another bureau official blamed the frequent blackouts in some suburbs on criminal activities. He said gangs had deliberately destroyed the electricity supply network and stolen power equipment. From January to July, Shenzhen reported more than 1,500 such cases. He said the gangs were highly organised and had cost the government more than 8 million yuan, but added that the bureau was working with police to protect the network.