Local authorities in areas from Chongqing to the Yangtze River Delta have drawn up emergency plans to cope with the impact of tomorrow's solar eclipse. Measures on crowd control, transport and telecommunications have been drawn up on instructions from the State Council. Police in Shanghai and two provincial capitals - Nanjing in Jiangsu, and Wuhan in Hubei - will adopt a 'nighttime model' as lights will be turned on to ensure traffic safety during the complete darkness, which is expected to last for up to six minutes. Traffic authorities in the three cities said public transport would operate as usual. 'Public transport, including buses, metros and taxis, will keep on running, but we will impose a stricter and more complete safety check on those vehicles in advance,' a spokesman for the Shanghai Transport and Port Bureau said. Shanghai's two airports, Hongqiao and Pudong, will also switch to night-flight mode to prevent flights being affected by the eclipse. Lights at the runways would be turned on, and pilots must operate according to the night-flight manual, Xinhua reported. Luo Jisheng, vice-director of the Hangzhou Tourism Bureau in Zhejiang, said the city was preparing to cope with large crowds of eclipse-watchers. 'We will be organising all of our managing staff to evacuate tourists if the site gets too crowded,' he said. The State Council on Saturday ordered relevant departments at various government levels to prepare fully for the inconveniences the eclipse could cause. The cabinet called on transport, railway and civil-aviation authorities to ensure smooth transport and passenger flow, and urged meteorological departments to step up weather monitoring and to issue timely forecasts. It also ordered tourism authorities to strengthen the regulation of travellers to prevent stampedes at observation spots. Some cities have also taken precautions to prevent telecommunications being affected or disrupted, as scientists warned that the ionosphere - the uppermost layer of the earth's atmosphere that is ionised by solar radiation - could be interrupted by the eclipse. Domestic media reported that Chongqing communications authorities were discouraging residents from making phone calls or sending text messages during the eclipse to avoid a communications bottleneck. Anji city in Zhejiang, which is said to be one of the best places to view the spectacle, will expand its telecommunications services to prevent disruptions. About the only thing that can ruin the spectacle is weather, and the National Astronomical Observatories said thunderstorms or thick clouds were expected for many cities in the Yangtze Delta region. A spokesman for the Hangzhou Meteorological Bureau said rain could obscure any view of the eclipse in the southern part of Hangzhou, but 'those in the northern part of the city might be able to view part of it'.