A farmer examines tomatoes at Hengda greenhouse in Shanghai, China May 25, 2021. At Chongming Island just outside Shanghai, China's most populous city, workers collect and pack tomatoes and cucumbers at a glass greenhouse operated by Dutch company FoodVentures, which harvested their first batch of produce at the site in May. REUTERS/Aly Song

A farmer gathers cucumbers at Hengda greenhouse in Shanghai, China May 25, 2021. The facility is one of dozens sprouting up on the outskirts of China's megacities that utilise high-end technology to manage irrigation, temperature and lighting systems to grow vegetables within easy reach of a large and affluent consumer base. REUTERS/Aly Song

A farmer gathers cucumbers at Hengda greenhouse in Shanghai, China May 25, 2021. By far the world's largest vegetable producer, China has used greenhouses for decades, but food supply disruptions sparked by coronavirus lockdowns in 2020 have accelerated the development of high-tech glass greenhouse facilities. REUTERS/Aly Song

A farmer transports cucumbers at Hengda greenhouse in Shanghai, China May 25, 2021. REUTERS/Aly Song

Peppers are seen at a greenhouse in Shanghai, China May 25, 2021. REUTERS/Aly Song

Farmers pack cucumbers at Hengda greenhouse in Shanghai, China May 25, 2021. REUTERS/Aly Song