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Stories about the lives we've made

module:Urban sustainability

Cities and the role of technology

page:Key indicators for sustainability

How can sustainability be measured?

Measuring sustainability is a key aspect for any decision maker, and achieving targets and monitoring of policies depends on indicators. Single and combined or multiple indicators may be used. The largest organisation globally involved with assessing sustainability indicators is the United Nations.

The UN definition of a sustainable city is as follows:

A sustainable city […] is a city where achievements in social, economic, and physical development are made to last. A sustainable city has a lasting supply of the natural resources on which its development depends (using them only at a level of sustainable yield). A sustainable city maintains a lasting security from environmental hazards which may threaten development achievements (allowing only for acceptable risk).

UN Habitat, UNHCS/UNHSP (United Nations Human Settlements Programme)

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The role of the UN-HABITAT organisation
    Cities are now home to half of humankind. They are hubs for much national production and consumption – economic and social processes that generate wealth and opportunity. But they also create disease, crime, pollution and poverty. In many cities, especially in developing countries, slum dwellers number more than 50 per cent of the population and have little or no access to shelter, water and sanitation. This is where UN-HABITAT is mandated to make a difference for the better.
    Habitat is concerned with improving the lives of at least 100 million slum dwellers by the year 2020.
    The agency's 2002/03 budget is US$300 million (from local and national governments and foundations).
    UN-HABITAT runs two major worldwide campaigns – the Global Campaign on Urban Governance and the Global Campaign for Secure Tenure. Through these campaigns and by other means, the agency focuses on a range of issues and special projects which it helps to implement. These include a joint UN-HABITAT/World Bank slum upgrading initiative called the Cities Alliance. This promotes effective housing development policies and strategies which help to develop and campaign for: housing rights, the promotion of sustainable cities, urban environmental planning and management, post-conflict land-management and reconstruction.
    The monitoring function is done through two main instruments: Global Urban Observatory and Statistics and Best Practices. The agency is participating in tracking Millennium Declaration goals by providing four indicators and a slum index based on them for Goal 7, target 11. Those indicators are:
    . percentage of people with access to sanitation
    . percentage of people with access to safe water
    . percentage of people with secure tenure
    . percentage of people in permanent housing/dwelling
From the United Nations Habitat website:


In summary, the UN suggests 23 key urban indicators and nine qualitative data subsets to assess sustainability (from the Istanbul Summit).

UN agencies define indicators and modes of data collection to assess sustainability. picture zoom © United Nations

Key indicators are both important for policy and relatively easy to collect. They are either numbers, or percentages and ratios, for example on topics such as water consumption, air pollution, wastewater treated or crime rates.

Qualitative data or checklists give an assessment of areas which cannot easily be measured quantitatively. For example community involvement in planning can be quantified and is. Often known as 'bottom-up' involvement, it comprises local people participating in decisions about their environment. This will be particularly important in cities with diverse or marginal ethnic and cultural groups.

Problems in data collection

Data is dynamic and often difficult to collect – not to mention an expensive process! Here are some of the main problems with data collection to measure sustainability. Overcoming these problems is vital for any city planner:

  • lack of city-based data, may only be available nationally
  • lack of contemporaneous data, meaning it may not all have been gathered at the same time/date
  • large number of organisations holding the data – some of whom may be biased towards certain types of data
  • different indicators selected by city authorities
  • inaccuracies in data collection
  • rapid change in statistics as cities evolve
  • cost in gathering data – which will penalise cities in LEDCs (Less Economically Developed Countries)

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UN agencies define indicators and modes of data collection to assess sustainability.
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