792 ITU‐T's Technical Reports and Specifications Dimension Definition/variables Infrastructure development The infrastructure development index combines two sub‐indices: one for infrastructure and another for housing. The infrastructure sub‐index includes: connection to services (piped water, sewage, electricity and ICT), waste management, knowledge infrastructure, health infrastructure, transport and road infrastructure. The housing sub‐index includes building materials and living space. Environmental sustainability The environmental sustainability index is made of four sub‐indices: air quality (PM10), CO2 emissions, energy and indoor pollution. Equity and social inclusion The equity and social inclusion index combines statistical measures of inequity of income/consumption (Gini coefficient) and social and gender inequity of access to services and infrastructure. Reference: UN Habitat report \"State of the World's cities 2012/2013 Prosperity of Cities\", Table 1.1.3, p 18. There is also an extended City Prosperity Index with more indicators and a plan to include Governance as a sixth dimension. Furthermore, specific work has been done on Streets as a driver for prosperity. UN Habitat (2013), State of the World's Cities 2012/2013, Prosperity of Cities: http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=3387 UN Habitat (2013), Streets as Public Spaces and Drivers of Urban Prosperity: http://www.unhabitat.org/pmss/listItemDetails.aspx?publicationID=3513