Asia 'megacities' face infrastructure timebomb: ADB

BANGKOK (AFP) - Asian nations must act quickly to protect their cities from flooding and other natural disasters as rapid urbanisation raises environmental risks, the Asian Development Bank said on Wednesday.

Major investment in infrastructure and smarter urban planning - focused on green growth - are the only routes to curbing the impact of such catastrophes as the region's metropolises expand, an ADB report said.

"Asia has seen unprecedented urban population growth, but this has been accompanied by immense stress on the environment," said ADB chief economist Changyong Rhee.

"The challenge now is to put in place policies which will reverse that trend and facilitate the development of green technology and green urbanisation," he added. "The (urbanisation) trend will continue at an enormously fast speed... Asian cities have very little time to prepare and build proper infrastructure."