Mexican journalist Javier Valdez, known for his award-winning coverage of the drug trade, has been shot dead. <br/><br/>Unidentified attackers opened fire on him yesterday in Culiacan city in the north-western state of Sinaloa, where he lived and worked. Valdez, 50, received the International Press Freedom Award from the Committee to Protect Journalists in 2011 for his work. He is one of several journalists who have been killed in Mexico this year.