Leading scholars have called for more efforts to be made in city planning to improve urban disaster relief capabilities in flooding and earthquakes while attending a World Expo theme forum that ended Monday in Wuxi, Jiangsu Province.

The two-day forum attracted about 600 participants to a discussion on how science and technology innovations will aid cities in the future.

Supachai Panitchpakdi, the Secretary-general of the United Nations Conference on Trade and Development (UNCTAD), said the mega-city is a leading phenomena in developing countries' urbanization, bringing not only huge pressure on the local environment, but also higher costs to both society and individuals.

A mega-city usually refers to cities with more than 10 million inhabitants or 2,000 inhabitants per square kilometer.

"The mega-cities might be crowded and less hygienic...Residents in slums might not have well-built homes, sufficient drinking water, proper drainage systems and other benefits that cities should provide," he said.

"Many cities are expanding with hardened roads that would not let water permeate through and without sufficient drainage systems," said Shan Chunchang, chairman of the Emergency Management Expert Group under China's State Council.

He cited the flooding ravaging southern China as an example. The flooding in southern China has left 175 people dead and 107 others missing by 8 a.m. Monday, said the Ministry of Civil Affairs.

"After the serious flooding in China in 1998, China has paid much attention to flood-fight work in major rivers, especially the Yangtze River, the Zhujiang (Pearl) River and the Heilongjiang River, but the weakest link showed up in small rivers and urban drainage systems as well as agricultural water conservancy," Shan said.

Flooding has ravaged Guangzhou, capital of south China's Guangdong Province, twice in half a month in May, submerging 13,000 cars, which caused automobile damages of about 100 million yuan (14.64 million U.S. dollars) to be paid in compensation.

In other provinces of Jiangxi, Fujian and Hunan, many citizens' cars, apartments and shops were inundated by water. Flooding also caused problems such as suspending train service and grain reserves have been soaked.

"Compared with flooding in 1998, now China is witnessing more flooding caused by rainfall in certain limited areas in a very short time. The flash flooding often occurred in cities where hardened roads and insufficient drainage systems could not let the water drain quickly," Shan said.

He showed pictures of the blizzards in 2008, which cut the service of a trunk railway and cut power to cities including Chenzhou, with about 5 million residents, in Hunan Province.

"China is experiencing quick urbanization and thus cities will be more vulnerable to natural disasters. For example, blizzards could easily cut off roads or power and affect many residents," Shan said.