London, November 30 (IANS) Global media freedom has fallen to the lowest level in at least a decade, according to a study that shows journalists are threatened by government censorship, organised crime and commercial pressures caused by the growth of the Internet. Turkey has experienced the biggest decline in freedom of speech over the past decade but Brazil, Burundi, Egypt, Poland, Venezuela and Bangladesh have also had a disturbing decline in the diversity and independence of the media, the Guardian quoted the study as saying on Thursday. "For the first time, we have a comprehensive and holistic overview of the state of freedom of expression and information around the world," said Thomas Hughes, the executive director of Article 19, the freedom of expression campaign group, which produced the study in collaboration with V-Dem, a political and social database. "Unfortunately, our findings show that freedom of expression is under attack in democracies as well as authoritarian regimes." The study's authors measured freedom of expression in 172 countries between 2006 and 2016 through a metric they have described as the Expression Agenda. This is based on 32 social and political indicators such as media bias and corruption, Internet censorship, access to justice, harassment of journalists and equality for social classes and genders. The study found that 259 journalists were jailed last year and 79 were killed, the Guardian reported. On a brighter note, Article 19 said there was improvement in some countries including Tunisia, Sri Lanka and Nepal, and also praised the introduction of freedom of information laws in 119 countries. Another group, the Committee to Protect Journalists, warned that there has "never been a more dangerous time to be a journalist".