Bangkok, Sept. 23 -- The World Bank (WB) on September 22 released a report recommending that Thailand step up investment in secondary cities such as Khon Kaen, Chiang Mai, Chonburi and Phuket, rather than continuing to concentrate resources in the increasingly congested capital Bangkok, with the aim of joining the group of high-income countries by 2037. According to the bank's "Thailand Cities of the Future: Urban Foundations for a High-Income Economy" report, Thailand's urban system remains heavily concentrated in Bangkok, which generates close to half of national output and is nearly 27 times larger than Chiang Mai, the country's second-largest city. This concentration has supported Thailand's economic development, but its costs are ris...