Environmental protection (EP) is defined as all activities directly aimed at the prevention, reduction and elimination of pollution or any other degradation of the environment. Statistics on environmental protection expenditure present data on the economic resources devoted by resident units to EP.

The data cover private and public specialised producers of EP services, the business sector, the general government sector and the household sector. The business sector is further broken down by economic activities. The data are cross-classified by EP classes (e.g. for wastewater management, waste management, protection of biodiversity and landscapes) following the Classification of Environmental Protection Activities (CEPA 2000).

In terms of economic transactions, the following variables are presented: total expenditure, total investments, pollution treatment investments, pollution prevention investments, total current expenditure, internal current expenditure, fees and purchases, receipts from by-products, subsidies/transfers and revenues.

For the period 1996-2012, European countries sent data every two years through the OECD/Eurostat Joint Questionnaire on Environmental Protection Expenditure and Revenues. From 2013 onwards, these data are collected on an annual basis.