The head of the Asian Development Bank says Asian cities need to make continuous efforts to become livable, competitive and environmentally sustainable.

Speaking before a forum at the regional lender’s Manila headquarters Tuesday, ADB President Haruhiko Kuroda noted that approximately 80 percent of gross domestic product comes from urban areas.

He said the “quality and efficiency” of the region’s cities, as well as their ability to innovate, will determine Asia’s “long-term productivity and overall stability.

The ADB says Asia is home to half the world’s megacities with populations of more than 10 million people. The bank says rapid urbanization is adding huge pressure on secondary cities which are growing the fastest, with more than 200 million urban dwellers living in poverty, many in grim city slums.

The ADB says cities are also threatened by worsening pollution and increasingly severe natural disasters due to climate change.