Seven people were killed by lightning or accidents caused by the rainfall, 87 towns and communities and nearly 3,580 hectares of farmland were flooded, and at least 138 flights and 14 trains were cancelled.

Traffic jams in the city centre, many parts of which were under water, caused tens of thousands of people to be late for work. One office worker was trapped in a bus for two hours and finally completed his journey to work in three hours - arriving an hour before lunch.

But the vehicles caught in traffic jams were luckier than some. More than 1,400 cars became submarines because their owners didn't have time to save them from underground garages that flooded. Local media reported that more than 18,000 vehicles suffered some degree of damage and that insurance payouts could total as much as 170 million yuan (HK$193 million).

On some university campuses, including the main campuses of Jinan University and Guangdong University of Foreign Studies in the city centre, students were woken by water pouring into ground-floor dormitory rooms. Many complained that personal property was damaged.

For the whole morning, even several hours after the rain stopped, they had to wade through water to get to their classrooms.

The end of the downpour did not end Guangzhou's ombrophobia. When the local observatory warned of the likelihood of more heavy rain on May 9 and 10, residents started to panic that the city, no stranger to summer rainstorms, was about to become Venice once again. In some residential communities, car owners rushed to move their cars from underground garages.

The city's water affairs bureau admitted that the public and media were right in blaming the flooding on the hundreds of construction sites dotted around the city, which had caused severe obstruction to its drainage system.

Officials said there were more than 2,000 construction projects in the city, including the laying of sewer pipes, paving of main streets, and, ironically, the construction of channels to improve the drainage system.

Some construction workers were found to have dumped rubble into the sewers, some had covered drain outlets with construction material and others had damaged the drainage system during their work.

City leaders and senior officials pledged they would, in future, punish construction firms that failed to take care of the drainage system.

Meanwhile, members of the public said the authorities' poor management of construction projects had contributed to the mess. It is generally believed that the rush to beautify the city ahead of the Asian Games is behind the launching of so many projects at the same time. People asked why the government, which cared so much about the height of skyscrapers and the colour and decoration of buildings along main streets, could not also pay attention to the sewers.

It is unfair to say that Guangzhou has ignored the problem. But even though it spent about 900 million yuan last year on improving its drainage system, the massive facelift ahead of the Asian Games and inefficient management have undone all that good work.

The challenge facing city officials in the next few months is how to convince residents that the same thing will not happen when the next storm comes.

People need solid proof that their shoes, clothes and even fridges will not float away in the middle of the night, their underground garages will not be flooded and that an improved sewer system will be able to deal with rain intensities seen only once every 50 years, let alone once every 10.

The next test might come very soon. From May to as late as November, coastal cities like Guangzhou can expect typhoons, bringing strong winds and more heavy rain.