A South African court ruled Thursday it was unconstitutional to ban an advertising campaign by an activist group urging President Jacob Zuma to stop the trade in lion bones. The adverts at Johannesburg\'s OR Tambo International Airport, the country\'s main port of entry, featured a lioness looking down the barrel of a gun with the text \"President Zuma can save her life.\" Airport authorities pulled down the posters in August 2012, just nine days into campaign group Avaaz\'s month-long contract. The Johannesburg High Court ordered that the adverts be reinstated after Avaaz accused Airports Company South Africa of violating its right to freedom of expression. \"This decision is a victory for citizens everywhere who now can begin, again, calling on President Zuma to end the brutal lion-bone trade, before lions are wiped out for good,\" said Avaaz campaign director Emma Ruby-Sachs. The global campaign group launched an online petition in June last year to get the government to act against the lion-bone trade. It claims South Africa is the largest exporter of lion bones, with a 250-percent increase in exports between 2009 and 2010. Lion bones are a hot commodity for their use in Asian medicine and to make \"bogus sex potions\", the group says. About 20,000 wild lions remain in Africa. The lion is listed as a \"vulnerable\" species by environmental group the International Union for Conservation of Nature, which estimates the population has decreased about 30 percent in the past two decades.