Cigarette companies have conspired for decades to defraud and mislead the public about the health risks of “light” and “low-tar” cigarettes, a federal appeals court said yesterday. The DC Circuit Court of Appeals unanimously ruled that a federal district judge was right to ban the terms from appearing on cigarette packages. Under the ruling, cigarette companies may soon be required to issue a public mea culpa admitting that they were killing people when they said cigarettes were safe and non-addictive.