2.2.4. City Development Index (CDI) and Human DevelopmentIndex (HDI)City Development Index (CDI) is a measure of average well-being and access to urban facilities by individuals (UN-Habitat,2002). The sub-indices, waste, health, and infrastructure, onlyreflects urban environmental conditions indirectly. As one of themost widely-used sustainability indicators, Human DevelopmentIndex (HDI) is a measure of life expectancy, income, and educa-tion (UNDP, 2009). Because of the limitation in data availability andquality, this index was computed only for four megacities—Beijing,Tianjin, Shanghai, and Chongqing.