Here is the list of the wealthiest and economically healthiest world's cities, according to Arcadis NV, a global design and consulting company. Arcadis ranks cities across three sectors of sustainability: People, planet and profit. So, basically, the 'people' sub-index rates social performance including quality of life. The 'planet' sub-index captures 'green' factors like energy, pollution and emissions. And the 'profit' sub-index assesses business environment and economic health.