Marijuana is illegal in most countries for a variety of reasons. One of the main reasons is that it is classified as a controlled substance, meaning that it is considered to have a high potential for abuse and no currently accepted medical use. This classification is based on the international drug control conventions, which were established in the 1961 Single Convention on Narcotic Drugs, and the 1971 Convention on Psychotropic Substances.
Another reason why marijuana is illegal in most countries is that it is considered to be a "gateway drug" that leads to the use of more dangerous drugs. This belief is based on the idea that marijuana use leads to a decreased perception of the risks associated with other drugs and that it leads to an increased likelihood of trying other drugs.
Moreover, many countries have criminalized marijuana based on moral, social and cultural reasons. It is considered to be a drug associated with deviance, crime, and anti-social behavior. In some countries, the criminalization of marijuana is driven by political and ideological reasons, where some governments view the drug as a threat to their authority, and want to criminalize it to maintain control over their citizens.
Finally, the illegal drug trade and organized crime groups that traffic marijuana and other drugs are also reasons why marijuana is illegal. These groups often use violence and intimidation to maintain control over the trade and