Providing a global picture of levels of cannabis cultivation and production remains a difficult task: although cannabis is produced in practically every country in the world, its cultivation is largely localized and, more often than not, feeds local markets.
Cannabis remains the most widely used illicit substance. There was a minor increase in the prevalence of cannabis users (180.6 million or 3.9 per cent of the population aged 15-64) as compared with previous estimates in 2009.
The areas of cannabis eradicated increased in the United States, possibly indicating an increase in the area under cultivation. Cultivation also seems to have gone up in the Americas as a whole. In South America, reported cannabis herb seizures rose by 46 per cent in 2011.
In Europe, seizures of cannabis herb increased, while seizures of cannabis resin ("hashish") went down. This may indicate that domestically produced cannabis continues to replace imported resin, mainly from Morocco. The production of cannabis resin seems to have stabilized and even declined in its main producing countries, i.e. Afghanistan and Morocco.
Many countries in Africa reported seizures of cannabis herb, with Nigeria reporting the largest quantities seized in the region.
In Europe, cannabis is generally cultivated outdoors in countries with favourable climatic conditions. In countries with less favourable climatic conditions, such as Belgium and the Netherlands, a larger number of indoor plants are found. It is difficult to compile an accurate picture of cultivation and eradication, as this varies widely across countries and climatic zones. Plant density fluctuates wildly, depending on the cultivation method (indoor or outdoor) and environmental factors.