This photo taken on February 26, 2019 shows an aerial view of a tea field in Zhangping in China's eastern Fujian province. (Photo by AFP Photo/China Stringer Network)

A man presents a self-made robot that local media reported is able to carry a person, in Heihe, Heilongjiang province, China, April 5, 2017. (Photo by Reuters/China Daily)

Performers are reflected in a displayed vehicle before going onto the stage during the Auto China 2016 auto show in Beijing, China, April 29, 2016. (Photo by Damir Sagolj/Reuters)

A fuel cell electric vehicle (FCEV) by Nissan is shown at China (Guangzhou) International Automobile Exhibition in Guangzhou, China November 18, 2016. (Photo by Bobby Yip/Reuters)

“The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a next generation of completely autonomous military aircraft, developed by Boeing's Phantom Works. Manufactured by Boeing Integrated Defense Systems, the X-45 was a part of DARPA's J-UCAS project”. – Wikipedia

Photo: Two X-45A Unmanned Combat Air Vehicles (UCAV) are shown to members of the news media July 11, 2002 at Edwards Air Force Base, California. The X-45A, developed by The Defense Advanced Research Projects Agency and the Boeing Company, is the first unmanned system designed from inception for combat missions. (Photo by David McNew/Getty Images)

A woman wearing a scarf to cover her face looks on as she waits for a passenger bus on a smoggy morning in New Delhi, India, November 8, 2017. The Great Smog of Delhi is an ongoing severe air-pollution event in New Delhi and adjoining areas in the National Capital Territory of India, in November 2017. Air pollution at this time peaked on both PM 2.5 and PM 10 levels. It has been reported as one of the worst levels of air quality in Delhi since 1999. (Photo by Saumya Khandelwal/Reuters)

CHINA: Customers eat at a restaurant as a cooked pig sits on a cart on the street outside in Hong Kong, China, December 12, 2016. (Photo by David Gray/Reuters)

People ride a boat on the Tianquan Lake during a foggy day in Xuyi in China's eastern Jiangsu province on November 20, 2019. (Photo by AFP Photo/China Stringer Network)