The United Nations Programme for Human Settlements (UN-HABITAT) developed the City Prosperity Initiative (the “Initiative”) as a framework to evaluate urban sustainable development through a new metric, the City Prosperity Index (CPI). At the UN-Habitat III conference in October 2016, the creators proposed to use the CPI  to complement the monitoring framework for Sustainable Development Goal 11: Make cities and human settlements inclusive, safe, resilient and sustainable” and other SDGs with urban based targets (UN-Habitat, 2015). In this blog post, we review the composition of the CPI and explore its potential to monitor progress toward the urban environmental components of the SDGs.

Applications of the CPI

The CPI is a composite indicator, based on six categories: a) Productivity (Pi), b) Infrastructure Development (Id), c) Quality of Life (Ql), d) Equity and Social Inclusion (Esi), e) Environmental Sustainability (Es) and f) Urban Governance and Legislation (Ugl). The indicators are calculated using city-level data and then are either used directly for the CPI calculation or standardized if needed. Each indicator results in a score between 1 and 100. The final CPI is obtained through aggregation as a unitless figure on a scale of 1 to 100, according to the equation below.

The Initiative has developed four variations on the CPI that vary in the number of indicators required, allowing practitioners to apply the appropriate CPI for their local circumstances and available data. The Global City Ranking (First variation) uses the fewest indicators (23), and the Initiative uses this version to compare cities. The February 2016 UN Habitat Global City Report documents the CPI Global City Ranking for 60 cities (15 cities in the Americas, 21 in Europe, 14 in Asia and Oceania, and 10 in Africa). The scores are summarized in Figure 1. City governments can evaluate their own cities using the Basic CPI (Second variation) with 36 indicators. The Extended CPI (Third variation) generates a more in-depth analysis using 66 indicators.

Figure 1: Map of CPI Results 2015 (Global City Ranking)

In addition to the Global City Ranking, several countries, including Mexico, Ecuador, Colombia, Saudi Arabia, and Ethiopia, have calculated Basic and Extended CPIs. The political context in each city has resulted in tweaks to the implementation approach. For example, in the case of Saudi Arabia, CPI data was collected not by the cities, but through a centralized effort run by the Ministry of Municipal and Rural Affairs. On the other hand, the Addis Ababa (Ethiopia) government calculated the CPI using existing information from local and national agencies with some indicators replaced by proxies, or not considered, due to the lack of data. These cases illustrate the flexibility of the CPI in different contexts. On the other hand, the increasing data collection requirements for the use CPI could also hinder opportunities for meaningful policy making and planning by local authorities; in that sense, potential users should make a careful analysis of the suitability of the tool and the additional resources needed, to allow for relevant metrics and analysis without creating a significant burden on data collection.

Environmental indicators of the CPI        

The environmental indicators of the CPI are closely related to the urban SDGs. For example, some indicators are directly taken from the targets of SDG 11, focused on sustainable cities. Other indicators are adapted from other SDGs such as the goal for clean water and sanitation and the goal for affordable and clean energy. Ultimately, the relative importance of environmental indicators in relation to the total number of indicators of the CPI is a reflection of the environmental urban issues addressed by the SDGs themselves.

The Extended City Prosperity Index is composed of 66 indicators, of which only 10[1] indicators are related to environmental conditions[2]. The summary of these indicators is detailed in Table 2.

Table 1 – Summary of Environmental Indicators of the CPI

Sub-Components Indicator Detail
Public Space 1. Green Area Per Capita The total green area per inhabitant.
2. Accessibility of Open Public Areas The percentage of the urban area located less than 300 meters away from an open public space.
Air Quality 1. Number of Monitoring Stations* The number of operative Fixed Automatic Monitoring Stations in the urban area.
2. PM 10 Concentration The annual daily mean of PM10 concentrations
3. CO2 Emissions Total CO2 emissions in a year per capita.
Waste Management 1. Solid Waste Collection* The percentage of the waste collected and adequately disposed of the total waste generated by the city.
2. Waste Water Treatment* The percentage of wastewater treated from wastewater produced within the urban agglomeration.
3. Solid Waste Recycling Share Percentage of recycled municipal waste of the total municipal waste.
Water and Energy 1. Share of Protected Areas in natural systems that provide basic ecosystem services* The percentage of a protected area that provides water to the city out of the total area of the water provider ecosystems.
2. Share of Renewable Energy Consumption* Percentage of electricity production from renewable sources[3] from the total electricity production (GWh generated).

Note: (*) Highlighted Indicators are used for the CPI Basic Scenario. (Source: UN Habitat – 2014)

However, as promising as the CPI is for monitoring SDG11, there are some deficiencies. The first one is related to oversimplification of some indicators and to the lack of additional information that could provide a more integral view of a component. For example, the requirements to only monitor PM10 and not any other air pollutants, to assess air quality, could inflate the scores of cities that emit other pollutants (CO, O3, NOx or SO2) but have low particulate matter, inaccurately portraying high air quality. Similarly, the absence of hazardous waste data in the waste collection indicator, limits the assessment to data to the waste collected from household and commerce, overlooks the impacts that inadequately managed industrial waste could be creating in the cities and surrounding environment.

Some indicators relate to resources for environmental management rather than the environmental performance of the city (i.e. the number of air quality monitoring stations and number of protected areas). Environmental management indicators bias the index towards cities with more resources devoted to environmental management, even if their actions have not led to improvements in the environmental conditions of their cities.

The CPI aggregates data for an entire city into a single score, rather than looking at differences between districts. This aggregation makes it difficult to see how pollution impacts different populations within the city. In that sense, the CPI fails to evaluate the distribution of environmental benefits and hazards throughout the city, their relation to income, race, and education levels, and ultimately take action to address those differences.

[1]    This includes 8 indicators in the Environmental Sustainability Component, plus two indicators from the Quality of Life Component related to Green Spaces and Access to Public Areas.

[2] If the basic scenario is chosen, only 5 out of 36 indicators would be environmental.

[3]    This does not include hydropower.