Programs to help farmers in developing countries grow legal crops as a substitute for illegal drugs do not work well enough, a UN drug control agency said in a report released on Wednesday.
Crop substitution programs, carried out mainly in Asia and Latin America to replace drug plantation, particularly opium poppies and coca leaves, "have not been very effective," said Hamid Ghodse, president of the International Narcotics Control Board (INCB) in the annual report.
The principles of alternative development should be rethought and "be applied in socially marginalized urban environments as well as in the remote rural areas," he said.
The program has neglected cannabis growers, for whom no policy was in place, he added.
Cannabis is the main illegal drug in Africa, abused by more than 34 million people. It is also popular elsewhere, with about 30 million people in the European Union, Iceland, Liechtenstein, Norway and Switzerland using it during the past year.
Most countries applying alternative development policies have seen a drop in growth of illicit crops, according to the report.
Worldwide opium poppy production excluding Afghanistan in 2004 was 32 percent of the total for 1994, and Thailand has seen a 98 percent decrease in poppy production in the past 40 years.
Almost all the heroin in Europe comes from Afghanistan, which also accounted for 87 percent of the global production of opium poppies in 2005, said the report.
The country is also seeing an increase in drug abuse, not only of opiates but also of prescription drugs.
The INCB also reported other developments in drug trafficking and use in Africa, where there was a significant growth in heroin abuse in Kenya, Mauritius and Tanzania.
In South Asia, drug abuse by injection is driving up the HIV/AIDS infection rate, in particular in Nepal and India.
In Central American countries, high unemployment and other social factors continue to make the region susceptible to drug traffickers and it continues to be a major transshipment point for cocaine originating from South America and bound for the United States.
In South America, illegal coca bush cultivation is increasing in Bolivia and Peru and cocaine production and drug trafficking have continued to spread in the region.
The INCB also highlighted the increasing presence of illegal online pharmacies. It identified the United States and some countries in Europe as the major markets for the illegal Internet pharmaceuticals.