The hot weather took its toll on some demonstrators, while the closure of roads along the route caused major congestion Of the 500,000 people who brought Hong Kong island to a standstill yesterday, not one person was arrested and less than 200 required medical assistance. As of 7.30pm, the Fire Services Department had sent ambulances to attend to 43 people who had fainted or had headaches and other minor injuries. Not all were admitted, but of those who were, 33 were at Ruttonjee Hospital, four at Pamela Youde Nethersole Eastern Hospital and one at Queen Mary Hospital. Police Chief Superintendent Tang How-kong said 33 demonstrators felt unwell and four twisted their ankles or wrists. One police officer also fainted due to the heat. The Red Cross received about 150 calls for medical assistance. Mr Tang said 1,300 officers were deployed to maintain order. They blocked one side of Hennessy Road at the beginning of the march, but cordoned off the other side later in the afternoon as the number of protesters swelled. The temperature reached a high of 32 degrees Celsius at 2.30pm before the march started. The Observatory had issued a hot weather warning and recommended that people avoid long periods in direct sunlight. Despite the arrangement of more frequent trains, hundreds of people gave up waiting for MTR trains at Admiralty and Wan Chai, and walked to Victoria Park. The MTR increased the frequency of trains from intervals of five minutes to three minutes on the island line. Other train lines were increased to four minute intervals. It also added more people to control the crowds. 'We have added more people at different stations, including Causeway Bay and Tin Hau,' an MTR spokeswoman said. 'We did get a large amount of passengers, but they were orderly.' The mass of people and closures of roads led to major congestion. All Kowloon Motor Bus cross-harbour services were delayed, a company spokesman said. The firm had arranged for buses to be diverted away from Causeway Bay and Wan Chai, but that did not help. The crowd was so large that many mobile phone networks reported heavy overload. 'It is not surprising that the network is busy if many people are calling at the same time,' a spokeswoman for the Office of Telecommunications Authority said. A representative at mobile telephone service provider SmarTone said the company received many complaints about calls not getting connected and said it was possible that too many people were trying to reach people at the march at the same time. The police also closed off parts of Gloucester Road, Hennessey Road, Paterson Street and Kingston Street. As of 8pm last night, the police said they had not received any reports of violence.