The combo photo shows Cai Lixin in 2012 when she worked in an electronics factory (up) and Cai posing in work clothes in a street in Shenzhen, south China's Guangdong Province, on Aug. 21, 2020 (bottom, photo taken by Mao Siqian). Cai Lixin left her home city Lufeng of Guangdong and came to Shenzhen with her elder sister in 2011. At first, she worked in an electronics factory which made mobile phones. In 2016, she changed her job and chose to be a takeaway delivery person. "Everyday, I ride through the city, enjoying the blue sky and the rich greenery while serving my customers. It's my happiest thing," she said. When China established the Shenzhen Special Economic Zone in 1980, its population was less than 30,000. Forty years later, it has developed into the biggest immigrant city in China housing 13 million with its GDP hitting 2.69 trillion yuan (about 389.4 billion U.S. dollars). (Xinhua)