In Ireland and the United Kingdom, housing associations are private, non-profit making organisations that provide low-cost "social housing" for people in need of a home. Any budget surplus is used to maintain existing housing and to help finance new homes and it cannot be used for personal benefit of directors or shareholders. Although independent, they are regulated by the state and commonly receive public funding. They are now the United Kingdom's major providers of new housing for rent, while many also run shared ownership schemes to help those who cannot afford to buy a home outright.
The natural environment or natural world encompasses all living and non-living things occurring naturally, meaning in this case not artificial. The term is most often applied to Earth or some parts of Earth. This environment encompasses the interaction of all living species, climate, weather and natural resources that affect human survival and economic activity.
An informal economy (informal sector or grey economy) is the part of any economy that is neither taxed nor monitored by any form of government. Although the informal sector makes up a significant portion of the economies in developing countries, it is sometimes stigmatized as troublesome and unmanageable. However, the informal sector provides critical economic opportunities for the poor and has been expanding rapidly since the 1960s. Integrating the informal economy into the formal sector is an important policy challenge.
A market economy is an economic system in which the decisions regarding investment, production and distribution to the consumers are guided by the price signals created by the forces of supply and demand. The major characteristic of a market economy is the existence of factor markets that play a dominant role in the allocation of capital and the factors of production.
Urban ecology is the scientific study of the relation of living organisms with each other and their surroundings in an urban environment. An urban environment refers to environments dominated by high-density residential and commercial buildings, paved surfaces, and other urban-related factors that create a unique landscape. The goal of urban ecology is to achieve a balance between human culture and the natural environment. Urban ecology is a recent field of study compared to ecology.