Off-duty officers at Huanggang Checkpoint donate blood at a blood donation center located at Shenzhen Book City CBD Store in Futian District on Tuesday. Since Shenzhen launched its first official drive to promote voluntary blood donation, more than 4 million blood donors have donated more than 800 tons of blood, rescuing 1.4 million patients. Shenzhen has become the first city in the country to achieve a 100 percent rate of blood donation for clinical use. Li Zhenqi |